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Electronic Colloquium on Computational Complexity

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REPORTS > 2023:
All reports in year 2023:
TR23-001 | 5th January 2023
Prerona Chatterjee, Pavel Hrubes

New Lower Bounds against Homogeneous Non-Commutative Circuits

We give several new lower bounds on size of homogeneous non-commutative circuits. We present an explicit homogeneous bivariate polynomial of degree $d$ which requires homogeneous non-commutative circuit of size $\Omega(d/\log d)$. For an $n$-variate polynomial with $n>1$, the result can be improved to $\Omega(nd)$, if $d\leq n$, or $\Omega(nd \frac{\log ... more >>>


TR23-002 | 5th January 2023
Noga Alon, Olivier Bousquet, Kasper Green Larsen, Shay Moran, Shlomo Moran

Diagonalization Games

Revisions: 2

We study several variants of a combinatorial game which is based on Cantor's diagonal argument. The game is between two players called Kronecker and Cantor. The names of the players are motivated by the known fact that Leopold Kronecker did not appreciate Georg Cantor's arguments about the infinite, and even ... more >>>


TR23-003 | 11th January 2023
Shachar Lovett, Jiapeng Zhang

Streaming Lower Bounds and Asymmetric Set-Disjointness

Frequency estimation in data streams is one of the classical problems in streaming algorithms. Following much research, there are now almost matching upper and lower bounds for the trade-off needed between the number of samples and the space complexity of the algorithm, when the data streams are adversarial. However, in ... more >>>


TR23-004 | 13th January 2023
Yinan Li, Youming Qiao, Avi Wigderson, Yuval Wigderson, Chuanqi Zhang

On linear-algebraic notions of expansion

A fundamental fact about bounded-degree graph expanders is that three notions of expansion---vertex expansion, edge expansion, and spectral expansion---are all equivalent. In this paper, we study to what extent such a statement is true for linear-algebraic notions of expansion.

There are two well-studied notions of linear-algebraic expansion, namely dimension expansion ... more >>>


TR23-005 | 13th January 2023
Paul Beame, Niels Kornerup

Cumulative Memory Lower Bounds for Randomized and Quantum Computation

Revisions: 2

Cumulative memory---the sum of space used over the steps of a computation---is a fine-grained measure of time-space complexity that is a more accurate measure of cost for algorithms with infrequent spikes in memory usage in the context of technologies such as cloud computing that allow dynamic allocation and de-allocation of ... more >>>


TR23-006 | 20th January 2023
Nader Bshouty

Superpolynomial Lower Bounds for Learning Monotone Classes

Revisions: 1

Koch, Strassle, and Tan [SODA 2023], show that, under the randomized exponential time hypothesis, there is no distribution-free PAC-learning algorithm that runs in time $n^{\tilde O(\log\log s)}$ for the classes of $n$-variable size-$s$ DNF, size-$s$ Decision Tree, and $\log s$-Junta by DNF (that returns a DNF hypothesis). Assuming a natural ... more >>>


TR23-007 | 3rd February 2023
Jan Krajicek

Extended Nullstellensatz proof systems

For a finite set $\cal F$ of polynomials over a fixed finite prime field of size $p$ containing all polynomials $x^2 - x$, a Nullstellensatz proof of the unsolvability of the system
$$
f = 0\ ,\ \mbox{ all } f \in {\cal F}
$$
is a linear combination ... more >>>


TR23-008 | 2nd February 2023
Ond?ej Ježil

Limits of structures and Total NP Search Problems

For a class of finite graphs, we define a limit object relative to some computationally restricted class of functions. The properties of the limit object then reflect how a computationally restricted viewer "sees" a generic instance from the class. The construction uses Krají?ek's forcing with random variables [7]. We prove ... more >>>


TR23-009 | 14th February 2023
Hervé Fournier, Nutan Limaye, Guillaume Malod, Srikanth Srinivasan, Sébastien Tavenas

Towards Optimal Depth-Reductions for Algebraic Formulas

Classical results of Brent, Kuck and Maruyama (IEEE Trans. Computers 1973) and Brent (JACM 1974) show that any algebraic formula of size s can be converted to one of depth O(log s) with only a polynomial blow-up in size. In this paper, we consider a fine-grained version of this result ... more >>>


TR23-010 | 13th February 2023
Per Austrin, Kilian Risse

Sum-of-Squares Lower Bounds for the Minimum Circuit Size Problem

We prove lower bounds for the Minimum Circuit Size Problem (MCSP) in the Sum-of-Squares (SoS) proof system. Our main result is that for every Boolean function $f: \{0,1\}^n \rightarrow \{0,1\}$, SoS requires degree $\Omega(s^{1-\epsilon})$ to prove that $f$ does not have circuits of size $s$ (for any $s > \text{poly}(n)$). ... more >>>


TR23-011 | 13th February 2023
Mikhail Dektiarev, Nikolay Vereshchagin

Half-duplex communication complexity with adversary? can be less than the classical communication complexity

Half-duplex communication complexity with adversary was defined in [Hoover, K., Impagliazzo, R., Mihajlin, I., Smal, A. V. Half-Duplex Communication Complexity, ISAAC 2018.] Half-duplex communication protocols generalize classical protocols defined by Andrew Yao in [Yao, A. C.-C. Some Complexity Questions Related to Distributive Computing (Preliminary Report), STOC 1979]. It has been ... more >>>


TR23-012 | 16th February 2023
Yogesh Dahiya, Vignesh K, Meena Mahajan, Karteek Sreenivasaiah

Linear threshold functions in decision lists, decision trees, and depth-2 circuits

We show that polynomial-size constant-rank linear decision trees (LDTs) can be converted to polynomial-size depth-2 threshold circuits LTF$\circ$LTF. An intermediate construct is polynomial-size decision lists that query a conjunction of a constant number of linear threshold functions (LTFs); we show that these are equivalent to polynomial-size exact linear decision lists ... more >>>


TR23-013 | 7th February 2023
Noam Mazor

A Lower Bound on the Share Size in Evolving Secret Sharing

Revisions: 1

Secret sharing schemes allow sharing a secret between a set of parties in a way that ensures that only authorized subsets of the parties learn the secret. Evolving secret sharing schemes (Komargodski, Naor, and Yogev [TCC ’16]) allow achieving this end in a scenario where the parties arrive in an ... more >>>


TR23-014 | 16th February 2023
Tameem Choudhury, Karteek Sreenivasaiah

Depth-3 Circuit Lower Bounds for k-OV

Revisions: 3

The 2-Orthogonal Vectors (2-OV) problem is the following: given two tuples $A$ and $B$ of $n$ vectors each of dimension $d$, decide if there exists a vector $u\in A$, and $v\in B$ such that $u$ and $v$ are orthogonal. This problem, and its generalization $k$-OV defined analogously for $k$ tuples, ... more >>>


TR23-015 | 20th February 2023
Scott Aaronson, Harry Buhrman, William Kretschmer

A Qubit, a Coin, and an Advice String Walk Into a Relational Problem

Revisions: 1

Relational problems (those with many possible valid outputs) are different from decision problems, but it is easy to forget just how different. This paper initiates the study of FBQP/qpoly, the class of relational problems solvable in quantum polynomial-time with the help of polynomial-sized quantum advice, along with its analogues for ... more >>>


TR23-016 | 22nd February 2023
Yuval Filmus, Edward Hirsch, Artur Riazanov, Alexander Smal, Marc Vinyals

Proving Unsatisfiability with Hitting Formulas

Hitting formulas have been studied in many different contexts at least since [Iwama 1989]. A hitting formula is a set of Boolean clauses such that any two of the clauses cannot be simultaneously falsified. [Peitl and Szeider 2022] conjectured that the family of unsatisfiable hitting formulas should contain the hardest ... more >>>


TR23-017 | 21st February 2023
Deepanshu Kush, Shubhangi Saraf

Near-Optimal Set-Multilinear Formula Lower Bounds

The seminal work of Raz (J. ACM 2013) as well as the recent breakthrough results by Limaye, Srinivasan, and Tavenas (FOCS 2021, STOC 2022) have demonstrated a potential avenue for obtaining lower bounds for general algebraic formulas, via strong enough lower bounds for set-multilinear formulas.

In this paper, we make ... more >>>


TR23-018 | 1st March 2023
Qipeng Liu, Ran Raz, Wei Zhan

Memory-Sample Lower Bounds for Learning with Classical-Quantum Hybrid Memory

In a work by Raz (J. ACM and FOCS 16), it was proved that any algorithm for parity learning on $n$ bits requires either $\Omega(n^2)$ bits of classical memory or an exponential number (in~$n$) of random samples. A line of recent works continued that research direction and showed that for ... more >>>


TR23-019 | 2nd March 2023
Pooya Hatami, William Hoza

Theory of Unconditional Pseudorandom Generators

Revisions: 2

This is a survey of unconditional *pseudorandom generators* (PRGs). A PRG uses a short, truly random seed to generate a long, "pseudorandom" sequence of bits. To be more specific, for each restricted model of computation (e.g., bounded-depth circuits or read-once branching programs), we would like to design a PRG that ... more >>>


TR23-020 | 3rd March 2023
Scott Aaronson, Shih-Han Hung

Certified Randomness from Quantum Supremacy

We propose an application for near-term quantum devices: namely, generating cryptographically certified random bits, to use (for example) in proof-of-stake cryptocurrencies. Our protocol repurposes the existing "quantum supremacy" experiments, based on random circuit sampling, that Google and USTC have successfully carried out starting in 2019. We show that, whenever the ... more >>>


TR23-021 | 9th March 2023
Karthik Gajulapalli, Alexander Golovnev, Satyajeet Nagargoje, Sidhant Saraogi

Range Avoidance for Constant-Depth Circuits: Hardness and Algorithms

Revisions: 2

Range Avoidance (AVOID) is a total search problem where, given a Boolean circuit $C\colon\{0,1\}^n\to\{0,1\}^m$, $m>n$, the task is to find a $y\in\{0,1\}^m$ outside the range of $C$. For an integer $k\geq 2$, $NC^0_k$-AVOID is a special case of AVOID where each output bit of $C$ depends on at most $k$ ... more >>>


TR23-022 | 11th March 2023
Jiatu Li, Igor Carboni Oliveira

Unprovability of strong complexity lower bounds in bounded arithmetic

While there has been progress in establishing the unprovability of complexity statements in lower fragments of bounded arithmetic, understanding the limits of Jerabek's theory $\textbf{APC}_1$ (2007) and of higher levels of Buss's hierarchy $\textbf{S}^i_2$ (1986) has been a more elusive task. Even in the more restricted setting of Cook's theory ... more >>>


TR23-023 | 13th March 2023
Xin Li

Two Source Extractors for Asymptotically Optimal Entropy, and (Many) More

Revisions: 1

A long line of work in the past two decades or so established close connections between several different pseudorandom objects and applications, including seeded or seedless non-malleable extractors, two source extractors, (bipartite) Ramsey graphs, privacy amplification protocols with an active adversary, non-malleable codes and many more. These connections essentially show ... more >>>


TR23-024 | 9th March 2023
Mark Bun, Nadezhda Voronova

Approximate degree lower bounds for oracle identification problems

Revisions: 1

The approximate degree of a Boolean function is the minimum degree of real polynomial that approximates it pointwise. For any Boolean function, its approximate degree serves as a lower bound on its quantum query complexity, and generically lifts to a quantum communication lower bound for a related function.

We ... more >>>


TR23-025 | 10th March 2023
Vikraman Arvind, Pushkar Joglekar

Multivariate to Bivariate Reduction for Noncommutative Polynomial Factorization

Based on a theorem of Bergman we show that multivariate noncommutative polynomial factorization is deterministic polynomial-time reducible to the factorization of bivariate noncommutative polynomials. More precisely, we show the following:

(1) In the white-box setting, given an n-variate noncommutative polynomial f in F over a field F (either a ... more >>>


TR23-026 | 15th March 2023
Shuichi Hirahara, Nobutaka Shimizu

Hardness Self-Amplification: Simplified, Optimized, and Unified

Strong (resp. weak) average-case hardness refers to the properties of a computational problem in which a large (resp. small) fraction of instances are hard to solve. We develop a general framework for proving hardness self-amplification, that is, the equivalence between strong and weak average-case hardness. Using this framework, we prove ... more >>>


TR23-027 | 8th March 2023
Joseph Zalewski

Some Lower Bounds Related to the Missing String Problem

We prove that a $O(k \log k)$-probe local algorithm for $k$-Missing String presented by Vyas and Williams is asymptotically optimal among a certain class of algorithms for this problem. The best lower bound we are aware of for the general case is still $\Omega(k)$.

more >>>

TR23-028 | 15th March 2023
Rahul Santhanam

An Algorithmic Approach to Uniform Lower Bounds

We propose a new family of circuit-based sampling tasks, such that non-trivial algorithmic solutions to certain tasks from this family imply frontier uniform lower bounds such as ``NP is not in uniform ACC^0" and ``NP does not have uniform polynomial-size depth-two threshold circuits". Indeed, the most general versions of our ... more >>>


TR23-029 | 18th March 2023
Nicollas Sdroievski, Dieter van Melkebeek

Instance-Wise Hardness versus Randomness Tradeoffs for Arthur-Merlin Protocols

A fundamental question in computational complexity asks whether probabilistic polynomial-time algorithms can be simulated deterministically with a small overhead in time (the BPP vs. P problem). A corresponding question in the realm of interactive proofs asks whether Arthur-Merlin protocols can be simulated nondeterministically with a small overhead in time (the ... more >>>


TR23-030 | 21st March 2023
Jan Krajicek

A proof complexity conjecture and the Incompleteness theorem

Given a sound first-order p-time theory $T$ capable of formalizing syntax of
first-order logic we define a p-time function $g_T$ that stretches all inputs by one
bit and we use its properties to show that $T$ must be incomplete. We leave it as an
open problem whether ... more >>>


TR23-031 | 23rd March 2023
Benny Applebaum, Eliran Kachlon, Arpita Patra

The Round Complexity of Statistical MPC with Optimal Resiliency

In STOC 1989, Rabin and Ben-Or (RB) established an important milestone in the fields of cryptography and distributed computing by showing that every functionality can be computed with statistical (information-theoretic) security in the presence of an active (aka Byzantine) rushing adversary that controls up to half of the parties. We ... more >>>


TR23-032 | 24th March 2023
Vishwas Bhargava, Shubhangi Saraf, Ilya Volkovich

Linear Independence, Alternants and Applications


We develop a new technique for analyzing linear independence of multivariate polynomials. One of our main technical contributions is a \emph{Small Witness for Linear Independence} (SWLI) lemma which states the following.
If the polynomials $f_1,f_2, \ldots, f_k \in \F[X]$ over $X=\{x_1, \ldots, x_n\}$ are $\F$-linearly independent then there exists ... more >>>


TR23-033 | 24th March 2023
Sumanta Ghosh, Prahladh Harsha, Simao Herdade, Mrinal Kumar, Ramprasad Saptharishi

Fast Numerical Multivariate Multipoint Evaluation

Revisions: 1

We design nearly-linear time numerical algorithms for the problem of multivariate multipoint evaluation over the fields of rational, real and complex numbers. We consider both \emph{exact} and \emph{approximate} versions of the algorithm. The input to the algorithms are (1) coefficients of an $m$-variate polynomial $f$ with degree $d$ in each ... more >>>


TR23-034 | 24th March 2023
Oded Goldreich

On teaching the approximation method for circuit lower bounds

Revisions: 1

This text provides a basic presentation of the the approximation method of Razborov (Matematicheskie Zametki, 1987) and its application by Smolensky (19th STOC, 1987) for proving lower bounds on the size of ${\cal AC}^0[p]$-circuits that compute sums mod~$q$ (for primes $q\neq p$).
The textbook presentations of the latter result ... more >>>


TR23-035 | 22nd March 2023
Shuichi Hirahara, Rahul Ilango, Zhenjian Lu, Mikito Nanashima, Igor Carboni Oliveira

A Duality Between One-Way Functions and Average-Case Symmetry of Information

Symmetry of Information (SoI) is a fundamental property of Kolmogorov complexity that relates the complexity of a pair of strings and their conditional complexities. Understanding if this property holds in the time-bounded setting is a longstanding open problem. In the nineties, Longpré and Mocas (1993) and Longpré and Watanabe (1995) ... more >>>


TR23-036 | 27th March 2023
Dean Doron, Roei Tell

Derandomization with Minimal Memory Footprint

Existing proofs that deduce BPL=L from circuit lower bounds convert randomized algorithms into deterministic algorithms with large constant overhead in space. We study space-bounded derandomization with minimal footprint, and ask what is the minimal possible space overhead for derandomization.
We show that $BPSPACE[S] \subseteq DSPACE[c \cdot S]$ for $c \approx ... more >>>


TR23-037 | 28th March 2023
Shuichi Hirahara

Capturing One-Way Functions via NP-Hardness of Meta-Complexity

A one-way function is a function that is easy to compute but hard to invert *on average*. We establish the first characterization of a one-way function by *worst-case* hardness assumptions, by introducing a natural meta-computational problem whose NP-hardness (and the worst-case hardness of NP) characterizes the existence of a one-way ... more >>>


TR23-038 | 28th March 2023
Rahul Ilango, Jiatu Li, Ryan Williams

Indistinguishability Obfuscation, Range Avoidance, and Bounded Arithmetic

The range avoidance problem (denoted by Avoid) asks to find a string outside of the range of a given circuit $C:\{0,1\}^n\to\{0,1\}^m$, where $m>n$. Although at least half of the strings of length $m$ are correct answers, it is not clear how to deterministically find one. Recent results of Korten (FOCS'21) ... more >>>


TR23-039 | 28th March 2023
Arkadev Chattopadhyay, Yogesh Dahiya, Meena Mahajan

Query Complexity of Search Problems

Revisions: 1

We relate various complexity measures like sensitivity, block sensitivity, certificate complexity for multi-output functions to the query complexities of such functions. Using these relations, we improve upon the known relationship between pseudo-deterministic query complexity and deterministic query complexity for total search problems: We show that pseudo-deterministic query complexity is at ... more >>>


TR23-040 | 28th March 2023
Edward Pyne, Ran Raz, Wei Zhan

Certified Hardness vs. Randomness for Log-Space

Let $\mathcal{L}$ be a language that can be decided in linear space and let $\epsilon >0$ be any constant. Let $\mathcal{A}$ be the exponential hardness assumption that for every $n$, membership in $\mathcal{L}$ for inputs of length~$n$ cannot be decided by circuits of size smaller than $2^{\epsilon n}$.
We ... more >>>


TR23-041 | 1st April 2023
Lila Fontes, Sophie Laplante, Mathieu Lauriere, Alexandre Nolin

The communication complexity of functions with large outputs

We study the two-party communication complexity of functions with large outputs, and show that the communication complexity can greatly vary depending on what output model is considered. We study a variety of output models, ranging from the open model, in which an external observer can compute the outcome, to the ... more >>>


TR23-042 | 3rd April 2023
Johan Håstad

On small-depth Frege proofs for PHP

We study Frege proofs for the one-to-one graph Pigeon Hole Principle
defined on the $n\times n$ grid where $n$ is odd.
We are interested in the case where each formula
in the proof is a depth $d$ formula in the basis given by
$\land$, $\lor$, and $\neg$. We prove that ... more >>>


TR23-043 | 9th April 2023
Yotam Dikstein, Irit Dinur

Coboundary and cosystolic expansion without dependence on dimension or degree

We give new bounds on the cosystolic expansion constants of several families of high dimensional expanders, and the known coboundary expansion constants of order complexes of homogeneous geometric lattices, including the spherical building of $SL_n(F_q)$. The improvement applies to the high dimensional expanders constructed by Lubotzky, Samuels and Vishne, and ... more >>>


TR23-044 | 28th March 2023
Sourav Chakraborty, Chandrima Kayal, Manaswi Paraashar

Separations between Combinatorial Measures for Transitive Functions

The role of symmetry in Boolean functions $f:\{0,1\}^n \to \{0,1\}$ has been extensively studied in complexity theory.
For example, symmetric functions, that is, functions that are invariant under the action of $S_n$ is an important class of functions in the study of Boolean functions.
A function $f:\{0,1\}^n \to \{0,1\}$ ... more >>>


TR23-045 | 13th April 2023
Vinayak Kumar

Tight Correlation Bounds for Circuits Between AC0 and TC0

Revisions: 1

We initiate the study of generalized $AC^0$ circuits comprised of arbitrary unbounded fan-in gates which only need to be constant over inputs of Hamming weight $\ge k$ (up to negations of the input bits), which we denote $GC^0(k)$. The gate set of this class includes biased LTFs like the $k$-$OR$ ... more >>>


TR23-046 | 13th April 2023
Yizhi Huang, Rahul Ilango, Hanlin Ren

NP-Hardness of Approximating Meta-Complexity: A Cryptographic Approach

It is a long-standing open problem whether the Minimum Circuit Size Problem ($\mathrm{MCSP}$) and related meta-complexity problems are NP-complete. Even for the rare cases where the NP-hardness of meta-complexity problems are known, we only know very weak hardness of approximation.

In this work, we prove NP-hardness of approximating meta-complexity with ... more >>>


TR23-047 | 2nd April 2023
Hunter Monroe

Ruling Out Short Proofs of Unprovable Sentences is Hard

If no optimal propositional proof system exists, we (and independently Pudlák) prove that ruling out length $t$ proofs of any unprovable sentence is hard. This mapping from unprovable to hard-to-prove sentences powerfully translates facts about noncomputability into complexity theory. For instance, because proving string $x$ is Kolmogorov random ($x{\in}R$) is ... more >>>


TR23-048 | 4th April 2023
Hadley Black, Deeparnab Chakrabarty, C. Seshadhri

A $d^{1/2+o(1)}$ Monotonicity Tester for Boolean Functions on $d$-Dimensional Hypergrids

Monotonicity testing of Boolean functions on the hypergrid, $f:[n]^d \to \{0,1\}$, is a classic topic in property testing. Determining the non-adaptive complexity of this problem is an important open question. For arbitrary $n$, [Black-Chakrabarty-Seshadhri, SODA 2020] describe a tester with query complexity $\widetilde{O}(\varepsilon^{-4/3}d^{5/6})$. This complexity is independent of $n$, but ... more >>>


TR23-049 | 17th April 2023
Mika Göös, Artur Riazanov, Anastasia Sofronova, Dmitry Sokolov

Top-Down Lower Bounds for Depth-Four Circuits

We present a top-down lower-bound method for depth-$4$ boolean circuits. In particular, we give a new proof of the well-known result that the parity function requires depth-$4$ circuits of size exponential in $n^{1/3}$. Our proof is an application of robust sunflowers and block unpredictability.

more >>>

TR23-050 | 18th April 2023
Manasseh Ahmed, Tsun-Ming Cheung, Hamed Hatami, Kusha Sareen

Communication complexity of half-plane membership

We study the randomized communication complexity of the following problem. Alice receives the integer coordinates of a point in the plane, and Bob receives the integer parameters of a half-plane, and their goal is to determine whether Alice's point belongs to Bob's half-plane.

This communication task corresponds to determining ... more >>>


TR23-051 | 18th April 2023
Benjamin Böhm, Olaf Beyersdorff

QCDCL vs QBF Resolution: Further Insights

We continue the investigation on the relations of QCDCL and QBF resolution systems. In particular, we introduce QCDCL versions that tightly characterise QU-Resolution and (a slight variant of) long-distance Q-Resolution. We show that most QCDCL variants - parameterised by different policies for decisions, unit propagations and reductions -- lead to ... more >>>


TR23-052 | 19th April 2023
Noah Fleming, Vijay Ganesh, Antonina Kolokolova, Chunxiao Li, Marc Vinyals

Limits of CDCL Learning via Merge Resolution

In their seminal work, Atserias et al. and independently Pipatsrisawat and Darwiche in 2009 showed that CDCL solvers can simulate resolution proofs with polynomial overhead. However, previous work does not address the tightness of the simulation, i.e., the question of how large this overhead needs to be. In this paper, ... more >>>


TR23-053 | 19th April 2023
Leroy Chew

Proof Simulation via Round-based Strategy Extraction for QBF

The proof complexity of Quantified Boolean Formulas (QBF) relates to both QBF solving and OBF certification. One method to p-simulate a QBF proof system is by formalising the soundness of its strategy extraction in propositional logic. In this work we illustrate how to use extended QBF Frege to simulate LD-Q(Drrs)-Res, ... more >>>


TR23-054 | 20th April 2023
Amey Bhangale, Subhash Khot, Dor Minzer

On Approximability of Satisfiable $k$-CSPs: III

In this paper we study functions on the Boolean hypercube that have the property that after applying certain random restrictions, the restricted function is correlated to a linear function with non-negligible probability. If the given function is correlated with a linear function then this property clearly holds. Furthermore, the property ... more >>>


TR23-055 | 20th April 2023
Amey Bhangale, Subhash Khot, Dor Minzer

On Approximability of Satisfiable $k$-CSPs: II

Revisions: 1

Let $\Sigma$ be an alphabet and $\mu$ be a distribution on $\Sigma^k$ for some $k \geq 2$. Let $\alpha > 0$ be the minimum probability of a tuple in the support of $\mu$ (denoted by $supp(\mu)$). Here, the support of $\mu$ is the set of all tuples in $\Sigma^k$ that ... more >>>


TR23-056 | 26th April 2023
Geoffrey Mon, Dana Moshkovitz, Justin Oh

Approximate Locally Decodable Codes with Constant Query Complexity and Nearly Optimal Rate

We present simple constructions of good approximate locally decodable codes (ALDCs) in the presence of a $\delta$-fraction of errors for $\delta<1/2$. In a standard locally decodable code $C \colon \Sigma_1^k \to \Sigma_2^n$, there is a decoder $M$ that on input $i \in [k]$ correctly outputs the $i$-th symbol of a ... more >>>


TR23-057 | 27th April 2023
Iddo Tzameret, Luming Zhang

Stretching Demi-Bits and Nondeterministic-Secure Pseudorandomness

We develop the theory of cryptographic nondeterministic-secure pseudorandomness beyond the point reached by Rudich's original work (Rudich 1997), and apply it to draw new consequences in average-case complexity and proof complexity. Specifically, we show the following:

?*Demi-bit stretch*: Super-bits and demi-bits are variants of cryptographic pseudorandom generators which are ... more >>>


TR23-058 | 23rd April 2023
Xin Li, Yan Zhong

Explicit Directional Affine Extractors and Improved Hardness for Linear Branching Programs

Affine extractors give some of the best-known lower bounds for various computational models, such as AC$^0$ circuits, parity decision trees, and general Boolean circuits. However, they are not known to give strong lower bounds for read-once branching programs (ROBPs). In a recent work, Gryaznov, Pudl\'{a}k, and Talebanfard (CCC' 22) introduced ... more >>>


TR23-060 | 17th April 2023
Sagnik Saha, Nikolaj Schwartzbach, Prashant Nalini Vasudevan

The Planted $k$-SUM Problem: Algorithms, Lower Bounds, Hardness Amplification, and Cryptography

Revisions: 1

In the average-case $k$-SUM problem, given $r$ integers chosen uniformly at random from $\{0,\ldots,M-1\}$, the objective is to find a set of $k$ numbers that sum to $0$ modulo $M$ (this set is called a ``solution''). In the related $k$-XOR problem, given $k$ uniformly random Boolean vectors of length $\log{M}$, ... more >>>


TR23-061 | 2nd May 2023
Abhimanyu Choudhury, Meena Mahajan

Dependency schemes in CDCL-based QBF solving: a proof-theoretic study

We formalize the notion of proof systems obtained by adding normal dependency schemes into the QCDCL proof system underlying algorithms for solving Quantified Boolean Formulas, by exploring the addition of the dependency schemes via two approaches: one as a preprocessing tool, and second in propagation and learnings in the QCDCL ... more >>>


TR23-062 | 2nd May 2023
Benny Applebaum, Eliran Kachlon

Conflict Checkable and Decodable Codes and Their Applications

Let $C$ be an error-correcting code over a large alphabet $q$ of block length $n$, and assume that, a possibly corrupted, codeword $c$ is distributively stored among $n$ servers where the $i$th entry is being held by the $i$th server. Suppose that every pair of servers publicly announce whether the ... more >>>


TR23-063 | 2nd May 2023
Jacobo Toran, Florian Wörz

Cutting Planes Width and the Complexity of Graph Isomorphism Refutations

The width complexity measure plays a central role in Resolution and other propositional proof systems like Polynomial Calculus (under the name of degree). The study of width lower bounds is the most extended method for proving size lower bounds, and it is known that for these systems, proofs with small ... more >>>


TR23-064 | 3rd May 2023
Oded Goldreich

On the Lower Bound on the Length of Relaxed Locally Decodable Codes

We revisit the known proof of the lower bound on the length of relaxed locally decodable codes, providing an arguably simpler exposition that yields a slightly better lower bound for the non-adaptive case and a weaker bound in the general case.

Recall that a locally decodable code is an error ... more >>>


TR23-065 | 4th May 2023
Louis Golowich

From Grassmannian to Simplicial High-Dimensional Expanders

Revisions: 1

In this paper, we present a new construction of simplicial complexes of subpolynomial degree with arbitrarily good local spectral expansion. Previously, the only known high-dimensional expanders (HDXs) with arbitrarily good expansion and less than polynomial degree were based on one of two constructions, namely Ramanujan complexes and coset complexes. ... more >>>


TR23-066 | 4th May 2023
Klim Efremenko, Gillat Kol, Dmitry Paramonov, Raghuvansh Saxena

Protecting Single-Hop Radio Networks from Message Drops

Single-hop radio networks (SHRN) are a well studied abstraction of communication over a wireless channel. In this model, in every round, each of the $n$ participating parties may decide to broadcast a message to all the others, potentially causing collisions. We consider the SHRN model in the presence of stochastic ... more >>>


TR23-067 | 7th May 2023
Guy Goldberg

Linear Relaxed Locally Decodable and Correctable Codes Do Not Need Adaptivity and Two-Sided Error

Revisions: 1

Relaxed locally decodable codes (RLDCs) are error-correcting codes in which individual bits of the message can be recovered by querying only a few bits from a noisy codeword.
Unlike standard (non-relaxed) decoders, a relaxed one is allowed to output a ``rejection'' symbol, indicating that the decoding failed.
To prevent the ... more >>>


TR23-068 | 10th May 2023
Ben Davis, Robert Robere

Colourful TFNP and Propositional Proofs

Revisions: 1

Recent work has shown that many of the standard TFNP classes — such as PLS, PPADS, PPAD, SOPL, and EOPL — have corresponding proof systems in propositional proof complexity, in the sense that a total search problem is in the class if and only if the totality of the problem ... more >>>


TR23-069 | 11th May 2023
Bruno Pasqualotto Cavalar, Igor Carboni Oliveira

Constant-depth circuits vs. monotone circuits

We establish new separations between the power of monotone and general (non-monotone) Boolean circuits:

- For every $k \geq 1$, there is a monotone function in ${\rm AC^0}$ (constant-depth poly-size circuits) that requires monotone circuits of depth $\Omega(\log^k n)$. This significantly extends a classical result of Okol'nishnikova (1982) and Ajtai ... more >>>


TR23-070 | 9th May 2023
Shuichi Hirahara, Zhenjian Lu, Hanlin Ren

Bounded Relativization

Relativization is one of the most fundamental concepts in complexity theory, which explains the difficulty of resolving major open problems. In this paper, we propose a weaker notion of relativization called *bounded relativization*. For a complexity class $C$, we say that a statement is *$C$-relativizing* if the statement holds relative ... more >>>


TR23-071 | 8th May 2023
Yuval Filmus, Itai Leigh, Artur Riazanov, Dmitry Sokolov

Sampling and Certifying Symmetric Functions

A circuit $\mathcal{C}$ samples a distribution $\mathbf{X}$ with an error $\epsilon$ if the statistical distance between the output of $\mathcal{C}$ on the uniform input and $\mathbf{X}$ is $\epsilon$. We study the hardness of sampling a uniform distribution over the set of $n$-bit strings of Hamming weight $k$ denoted by $\mathbf{U}^n_k$ ... more >>>


TR23-072 | 18th May 2023
Yeyuan Chen, Yizhi Huang, Jiatu Li, Hanlin Ren

Range Avoidance, Remote Point, and Hard Partial Truth Tables via Satisfying-Pairs Algorithms

The *range avoidance problem*, denoted as $\mathcal{C}$-$\rm Avoid$, asks to find a non-output of a given $\mathcal{C}$-circuit $C:\{0,1\}^n\to\{0,1\}^\ell$ with stretch $\ell>n$. This problem has recently received much attention in complexity theory for its connections with circuit lower bounds and other explicit construction problems. Inspired by the Algorithmic Method for circuit ... more >>>


TR23-073 | 15th May 2023
Xi Chen, Yuhao Li, Mihalis Yannakakis

Reducing Tarski to Unique Tarski (in the Black-box Model)

We study the problem of finding a Tarski fixed point over the $k$-dimensional grid $[n]^k$. We give a black-box reduction from the Tarski problem to the same problem with an additional promise that the input function has a unique fixed point. It implies that the Tarski problem and the unique ... more >>>


TR23-074 | 14th May 2023
Abhibhav Garg, Rafael Mendes de Oliveira, Shir Peleg, Akash Sengupta

Radical Sylvester-Gallai Theorem for Tuples of Quadratics

We prove a higher codimensional radical Sylvester-Gallai type theorem for quadratic polynomials, simultaneously generalizing [Han65, Shp20]. Hansen's theorem is a high-dimensional version of the classical Sylvester-Gallai theorem in which the incidence condition is given by high-dimensional flats instead of lines. We generalize Hansen's theorem to the setting of quadratic forms ... more >>>


TR23-075 | 17th May 2023
Abhranil Chatterjee, Sumanta Ghosh, Rohit Gurjar, Roshan Raj

Border Complexity of Symbolic Determinant under Rank One Restriction

VBP is the class of polynomial families that can be computed by the determinant of a symbolic matrix of the form $A_0 + \sum_{i=1}^n A_ix_i$ where the size of each $A_i$ is polynomial in the number of variables (equivalently, computable by polynomial-sized algebraic branching programs (ABP)). A major open problem ... more >>>


TR23-076 | 24th May 2023
Lijie Chen, Zhenjian Lu, Igor Carboni Oliveira, Hanlin Ren, Rahul Santhanam

Polynomial-Time Pseudodeterministic Construction of Primes

A randomized algorithm for a search problem is *pseudodeterministic* if it produces a fixed canonical solution to the search problem with high probability. In their seminal work on the topic, Gat and Goldwasser posed as their main open problem whether prime numbers can be pseudodeterministically constructed in polynomial time.

... more >>>

TR23-077 | 25th May 2023
Nir Bitansky, Chethan Kamath, Omer Paneth, Ron Rothblum, Prashant Nalini Vasudevan

Batch Proofs are Statistically Hiding

Revisions: 4

Batch proofs are proof systems that convince a verifier that $x_1,\dots, x_t \in L$, for some $NP$ language $L$, with communication that is much shorter than sending the $t$ witnesses. In the case of statistical soundness (where the cheating prover is unbounded but honest prover is efficient), interactive batch proofs ... more >>>


TR23-078 | 30th May 2023
Or Meir

Toward Better Depth Lower Bounds: A KRW-like theorem for Strong Composition

Revisions: 3

One of the major open problems in complexity theory is proving super-logarithmic lower bounds on the depth of circuits (i.e., $\mathbf{P}\not\subseteq \mathbf{NC}^{1}$). Karchmer, Raz, and Wigderson (Computational Complexity 5(3/4), 1995) suggested to approach this problem by proving that depth complexity of a composition of functions $f \diamond g$ is roughly ... more >>>


TR23-079 | 31st May 2023
Russell Impagliazzo, Valentine Kabanets, Ilya Volkovich

Mutual Empowerment between Circuit Obfuscation and Circuit Minimization

We study close connections between Indistinguishability Obfuscation ($IO$) and the Minimum Circuit Size Problem ($MCSP$), and argue that algorithms for one of $MCSP$ or $IO$ would empower the other one. Some of our main results are:

\begin{itemize}
\item If there exists a perfect (imperfect) $IO$ that is computationally secure ... more >>>


TR23-080 | 1st June 2023
Halley Goldberg, Valentine Kabanets

Improved Learning from Kolmogorov Complexity

Carmosino, Impagliazzo, Kabanets, and Kolokolova (CCC, 2016) showed that the existence of natural properties in the sense of Razborov and Rudich (JCSS, 1997) implies PAC learning algorithms in the sense of Valiant (Comm. ACM, 1984), for boolean functions in $\P/\poly$, under the uniform distribution and with membership queries. It is ... more >>>


TR23-081 | 1st June 2023
Noga Amit, Guy Rothblum

Constant-Round Arguments from One-Way Functions

Revisions: 1

We study the following question: what cryptographic assumptions are needed for obtaining constant-round computationally-sound argument systems? We focus on argument systems with almost-linear verification time for subclasses of $\mathbf{P}$, such as depth-bounded computations.
Kilian's celebrated work [STOC 1992] provides such 4-message arguments for $\mathbf{P}$ (actually, for $\mathbf{NP}$) using collision-resistant hash ... more >>>


TR23-082 | 1st June 2023
Ryan Williams

Self-Improvement for Circuit-Analysis Problems

Many results in fine-grained complexity reveal intriguing consequences from solving various SAT problems even slightly faster than exhaustive search. We prove a ``self-improving'' (or ``bootstrapping'') theorem for Circuit-SAT, $\#$Circuit-SAT, and its fully-quantified version: solving one of these problems faster for ``large'' circuit sizes implies a significant speed-up for ``smaller'' circuit ... more >>>


TR23-083 | 2nd June 2023
Srinivasan A, Uma Girish

Trade-offs between Entanglement and Communication

We study the advantages of quantum communication models over classical communication models that are equipped with a limited number of qubits of entanglement. In this direction, we give explicit partial functions on $n$ bits for which reducing the entanglement increases the classical communication complexity exponentially. Our separations are as follows. ... more >>>


TR23-084 | 31st May 2023
Itai Dinur

Time-Space Lower Bounds for Bounded-Error Computation in the Random-Query Model

Revisions: 1

The random-query model was introduced by Raz and Zhan at ITCS 2020 as a new model of space-bounded computation. In this model, a branching program of length $T$ and width $2^{S}$ attempts to compute a function $f:\{0,1\}^n \rightarrow \{0,1 \}$. However, instead of receiving direct access to the input bits ... more >>>


TR23-085 | 4th June 2023
Ari Karchmer

Average-Case PAC-Learning from Nisan's Natural Proofs

Revisions: 2

Carmosino et al. (2016) demonstrated that natural proofs of circuit lower bounds imply algorithms for learning circuits with membership queries over the uniform distribution. Indeed, they exercised this implication to obtain a quasi-polynomial time learning algorithm for ${AC}^0[p]$ circuits, for any prime $p$, by leveraging the existing natural proofs from ... more >>>


TR23-086 | 8th June 2023
Dmitry Sokolov

Random $(\log n)$-CNF are Hard for Cutting Planes (Again)

The random $\Delta$-CNF model is one of the most important distribution over $\Delta\text{-}\mathrm{SAT}$ instances. It is closely connected to various areas of computer science, statistical physics, and is a benchmark for satisfiability algorithms. Fleming, Pankratov, Pitassi, and Robere and independently Hrubes and Pudlak showed that when $\Delta = \Theta(\log n)$, ... more >>>


TR23-087 | 9th June 2023
Benny Applebaum, Oded Nir, Benny Pinkas

How to Recover a Secret with $O(n)$ Additions

Revisions: 1

Threshold cryptography is typically based on the idea of secret-sharing a private-key $s\in F$ ``in the exponent'' of some cryptographic group $G$, or more generally, encoding $s$ in some linearly homomorphic domain. In each invocation of the threshold system (e.g., for signing or decrypting) an ``encoding'' of the secret is ... more >>>


TR23-088 | 1st June 2023
Parker Newton, Silas Richelson, Chase Wilson

A High Dimensional Goldreich-Levin Theorem

In this work we prove a high dimensional analogue of the beloved Goldreich-Levin theorem (STOC 1989). We consider the following algorithmic problem: given oracle access to a function $f:\mathbb{Z}_q^m\rightarrow\mathbb{Z}_q^n$ such that ${\rm Prob}_{{\bf x}\sim\mathbb{Z}_q^m}\bigl[f({\bf x})={\bf Ax}\bigr]\geq\varepsilon$ for some ${\bf A}\in\mathbb{Z}_q^{n\times m}$ and $\varepsilon>0$, recover ${\bf A}$ (or a list of ... more >>>


TR23-089 | 15th June 2023
Louis Golowich

New Explicit Constant-Degree Lossless Expanders

Revisions: 1

We present a new explicit construction of onesided bipartite lossless expanders of constant degree, with arbitrary constant ratio between the sizes of the two vertex sets. Our construction is simpler to state and analyze than the prior construction of Capalbo, Reingold, Vadhan, and Wigderson (2002).

We construct our ... more >>>


TR23-090 | 15th June 2023
Itay Cohen, Roy Roth, Amnon Ta-Shma

HDX Condensers

More than twenty years ago, Capalbo, Reingold, Vadhan and Wigderson gave the first (and up to date only) explicit construction of a bipartite expander with almost full combinatorial expansion. The construction incorporates zig-zag ideas together with extractor technology, and is rather complicated. We give an alternative construction that builds upon ... more >>>


TR23-091 | 18th June 2023
Benny Applebaum, Amos Beimel, Yuval Ishai, Eyal Kushilevitz, Tianren Liu, Vinod Vaikuntanathan

Succinct Computational Secret Sharing

A secret-sharing scheme enables a dealer to share a secret $s$ among $n$ parties such that only authorized subsets of parties, specified by a monotone access structure $f:\{0,1\}^n\to\{0,1\}$, can reconstruct $s$ from their shares. Other subsets of parties learn nothing about $s$.

The question of minimizing the (largest) share size ... more >>>


TR23-092 | 28th June 2023
Swastik Kopparty, Vishvajeet N

Extracting Mergers and Projections of Partitions

We study the problem of extracting randomness from somewhere random sources, and related combinatorial phenomena: partition analogues of Shearer's lemma on projections.

A somewhere-random source is a tuple $(X_1, \ldots, X_t)$ of (possibly correlated) $\{0,1\}^n$-valued random variables $X_i$ where for some unknown $i \in [t]$, $X_i$ is guaranteed to be ... more >>>


TR23-093 | 29th June 2023
Vinayak Kumar, Geoffrey Mon

Relaxed Local Correctability from Local Testing

We cement the intuitive connection between relaxed local correctability and local testing by presenting a concrete framework for building a relaxed locally correctable code from any family of linear locally testable codes with sufficiently high rate. When instantiated using the locally testable codes of Dinur et al. (STOC 2022), this ... more >>>


TR23-094 | 29th June 2023
Lijie Chen, Roei Tell

New ways of studying the BPP = P conjecture

What's new in the world of derandomization? Questions about pseudorandomness and derandomization have been driving progress in complexity theory for many decades. In this survey we will describe new approaches to the $\mathcal{BPP}=\mathcal{P}$ conjecture from recent years, as well as new questions, algorithmic approaches, and ways of thinking. For example: ... more >>>


TR23-095 | 21st June 2023
David Heath, Vladimir Kolesnikov, Rafail Ostrovsky

Tri-State Circuits: A Circuit Model that Captures RAM

We introduce tri-state circuits (TSCs). TSCs form a natural model of computation that, to our knowledge, has not been considered by theorists. The model captures a surprising combination of simplicity and power. TSCs are simple in that they allow only three wire values ($0$,$1$, and undefined – $Z$) and three ... more >>>


TR23-096 | 28th June 2023
Huacheng Yu, Wei Zhan

Randomized vs. Deterministic Separation in Time-Space Tradeoffs of Multi-Output Functions

We prove the first polynomial separation between randomized and deterministic time-space tradeoffs of multi-output functions. In particular, we present a total function that on the input of $n$ elements in $[n]$, outputs $O(n)$ elements, such that:

- There exists a randomized oblivious algorithm with space $O(\log n)$, time $O(n\log n)$ ... more >>>


TR23-097 | 2nd July 2023
Joshua Cook, Ron D. Rothblum

Efficient Interactive Proofs for Non-Deterministic Bounded Space

Revisions: 1

The celebrated $\mathbf{IP}=\mathbf{PSPACE}$ Theorem gives an efficient interactive proof for any bounded-space algorithm. In this work we study interactive proofs for non-deterministic bounded space computations. While Savitch's Theorem shows that nondeterministic bounded-space algorithms can be simulated by deterministic bounded-space algorithms, this simulation has a quadratic overhead. We give interactive protocols ... more >>>


TR23-098 | 5th July 2023
Andrej Bogdanov, Pravesh Kothari, Alon Rosen

Public-Key Encryption, Local Pseudorandom Generators, and the Low-Degree Method

The low-degree method postulates that no efficient algorithm outperforms low-degree polynomials in certain hypothesis-testing tasks. It has been used to understand computational indistinguishability in high-dimensional statistics.

We explore the use of the low-degree method in the context of cryptography. To this end, we apply it in the design and analysis ... more >>>


TR23-099 | 8th July 2023
Sourav Chakraborty, Chandrima Kayal, Rajat Mittal, Manaswi Paraashar, Swagato Sanyal, Nitin Saurabh

On the Composition of Randomized Query Complexity and Approximate Degree

Revisions: 1

For any Boolean functions $f$ and $g$, the question whether $\text{R}(f\circ g) = \tilde{\Theta}(\text{R}(f) \cdot \text{R}(g))$, is known as the composition question for the randomized query complexity. Similarly, the composition question for the approximate degree asks whether $\widetilde{\text{deg}}(f\circ g) = \tilde{\Theta}(\widetilde{\text{deg}}(f)\cdot\widetilde{\text{deg}}(g))$. These questions are two of the most important and ... more >>>


TR23-100 | 6th July 2023
Shuichi Hirahara, Mikito Nanashima

Learning in Pessiland via Inductive Inference

Pessiland is one of Impagliazzo's five possible worlds in which NP is hard on average, yet no one-way function exists. This world is considered the most pessimistic because it offers neither algorithmic nor cryptographic benefits.

In this paper, we develop a unified framework for constructing strong learning algorithms ... more >>>


TR23-101 | 5th July 2023
Renato Ferreira Pinto Jr.

Directed Poincaré Inequalities and $L^1$ Monotonicity Testing of Lipschitz Functions

We study the connection between directed isoperimetric inequalities and monotonicity testing. In recent years, this connection has unlocked breakthroughs for testing monotonicity of functions defined on discrete domains. Inspired the rich history of isoperimetric inequalities in continuous settings, we propose that studying the relationship between directed isoperimetry and monotonicity in ... more >>>


TR23-102 | 13th July 2023
Chin Ho Lee, Edward Pyne, Salil Vadhan

On the Power of Regular and Permutation Branching Programs

We give new upper and lower bounds on the power of several restricted classes of arbitrary-order read-once branching programs (ROBPs) and standard-order ROBPs (SOBPs) that have received significant attention in the literature on pseudorandomness for space-bounded computation.

Regular SOBPs of length $n$ and width $\lfloor w(n+1)/2\rfloor$ can exactly simulate general ... more >>>


TR23-103 | 12th July 2023
Yanyi Liu, Rafael Pass

On One-way Functions and the Worst-case Hardness of Time-Bounded Kolmogorov Complexity

Revisions: 1

Whether one-way functions (OWF) exist is arguably the most important
problem in Cryptography, and beyond. While lots of candidate
constructions of one-way functions are known, and recently also
problems whose average-case hardness characterize the existence of
OWFs have been demonstrated, the question of
whether there exists some \emph{worst-case hard problem} ... more >>>


TR23-104 | 14th July 2023
Meghal Gupta, Rachel Zhang

A Noise Resilient Transformation for Streaming Algorithms

In a streaming algorithm, Bob receives an input $x \in \{0,1\}^n$ via a stream and must compute a function $f$ in low space. However, this function may be fragile to errors in the input stream. In this work, we investigate what happens when the input stream is corrupted. Our main ... more >>>


TR23-105 | 13th July 2023
Lijie Chen, Roei Tell, Ryan Williams

Derandomization vs Refutation: A Unified Framework for Characterizing Derandomization

We establish an equivalence between two algorithmic tasks: *derandomization*, the deterministic simulation of probabilistic algorithms; and *refutation*, the deterministic construction of inputs on which a given probabilistic algorithm fails to compute a certain hard function.

We prove that refuting low-space probabilistic streaming algorithms that try to compute functions $f\in\mathcal{FP}$ ... more >>>


TR23-106 | 17th July 2023
Mika Göös, Ziyi Guan, Tiberiu Mosnoi

Depth-3 Circuits for Inner Product

What is the $\Sigma_3^2$-circuit complexity (depth 3, bottom-fanin 2) of the $2n$-bit inner product function? The complexity is known to be exponential $2^{\alpha_n n}$ for some $\alpha_n=\Omega(1)$. We show that the limiting constant $\alpha=\limsup \alpha_n$ satisfies
\[
0.847... ~\leq~ \alpha ~\leq~ 0.965...\ .
\]
Determining $\alpha$ is one of the ... more >>>


TR23-107 | 20th July 2023
Uma Girish, Ran Raz, Wei Zhan

Quantum Logspace Computations are Verifiable

In this note, we observe that quantum logspace computations are verifiable by classical logspace algorithms, with unconditional security. More precisely, every language in BQL has an information-theoretically secure) streaming proof with a quantum logspace prover and a classical logspace verifier. The prover provides a polynomial-length proof that is streamed to ... more >>>


TR23-108 | 21st July 2023
Andrej Bogdanov, Tsun-Ming Cheung, Krishnamoorthy Dinesh, John C.S. Lui

Classical simulation of one-query quantum distinguishers

We study the relative advantage of classical and quantum distinguishers of bounded query complexity over $n$-bit strings, focusing on the case of a single quantum query. A construction of Aaronson and Ambainis (STOC 2015) yields a pair of distributions that is $\epsilon$-distinguishable by a one-query quantum algorithm, but $O(\epsilon k/\sqrt{n})$-indistinguishable ... more >>>


TR23-109 | 21st July 2023
Pranav Bisht, Nikhil Gupta, Ilya Volkovich

Towards Identity Testing for Sums of Products of Read-Once and Multilinear Bounded-Read Formulae

An arithmetic formula is an arithmetic circuit where each gate has fan-out one. An \emph{arithmetic read-once formula} (ROF in short) is an arithmetic formula where each input variable labels at most one leaf. In this paper we present several efficient blackbox \emph{polynomial identity testing} (PIT) algorithms for some classes of ... more >>>


TR23-110 | 25th July 2023
Gil Cohen, Tal Yankovitz

Asymptotically-Good RLCCs with $(\log{n})^{2+o(1)}$ Queries

Recently, Kumar and Mon reached a significant milestone by constructing asymptotically good relaxed locally correctable codes (RLCCs) with poly-logarithmic query complexity. Specifically, they constructed $n$-bit RLCCs with $O(\log^{69}n)$ queries. This significant advancement relies on a clever reduction to locally testable codes (LTCs), capitalizing on recent breakthrough works in LTCs.

With ... more >>>


TR23-111 | 29th July 2023
Vaibhav Krishan

$\mathit{MidBit}^+$, Torus Polynomials and Non-classical Polynomials: Equivalences for $\mathit{ACC}$ Lower Bounds

We give a conversion from non-classical polynomials to $\mathit{MidBit}^+$ circuits and vice-versa. This conversion, along with previously known results, shows that torus polynomials, non-classical polynomials and $\mathit{MidBit}^+$ circuits can all be converted to each other. Therefore lower bounds against any of these models lead to lower bounds against all three ... more >>>


TR23-112 | 30th July 2023
Amey Bhangale, Subhash Khot, Dor Minzer

On Approximability of Satisfiable k-CSPs: IV

We prove a stability result for general $3$-wise correlations over distributions satisfying mild connectivity properties. More concretely, we show that if $\Sigma,\Gamma$ and $\Phi$ are alphabets of constant size, and $\mu$ is a pairwise connected distribution over $\Sigma\times\Gamma\times\Phi$ with no $(\mathbb{Z},+)$ embeddings in which the probability of each atom is ... more >>>


TR23-113 | 8th August 2023
Justin Holmgren, Ron Rothblum

Linear-Size Boolean Circuits for Multiselection

We study the circuit complexity of the multiselection problem: given an input string $x \in \{0,1\}^n$ along with indices $i_1,\dots,i_q \in [n]$, output $(x_{i_1},\dots,x_{i_q})$. A trivial lower bound for the circuit size is the input length $n + q \cdot \log(n)$, but the straightforward construction has size $\Theta(q \cdot n)$.

... more >>>

TR23-114 | 8th August 2023
Lijie Chen, William Hoza, Xin Lyu, Avishay Tal, Hongxun Wu

Weighted Pseudorandom Generators via Inverse Analysis of Random Walks and Shortcutting

A weighted pseudorandom generator (WPRG) is a generalization of a pseudorandom generator (PRG) in which, roughly speaking, probabilities are replaced with weights that are permitted to be positive or negative. We present new explicit constructions of WPRGs that fool certain classes of standard-order read-once branching programs. In particular, our WPRGs ... more >>>


TR23-115 | 8th August 2023
Abhranil Chatterjee, Mrinal Kumar, Ben Lee Volk

Determinants vs. Algebraic Branching Programs

Revisions: 1

We show that for every homogeneous polynomial of degree $d$, if it has determinantal complexity at most $s$, then it can be computed by a homogeneous algebraic branching program (ABP) of size at most $O(d^5s)$. Moreover, we show that for \textit{most} homogeneous polynomials, the width of the resulting homogeneous ABP ... more >>>


TR23-116 | 12th August 2023
Amey Bhangale, Subhash Khot, Dor Minzer

Effective Bounds for Restricted $3$-Arithmetic Progressions in $\mathbb{F}_p^n$

For a prime $p$, a restricted arithmetic progression in $\mathbb{F}_p^n$ is a triplet of vectors $x, x+a, x+2a$ in which the common difference $a$ is a non-zero element from $\{0,1,2\}^n$. What is the size of the largest $A\subseteq \mathbb{F}_p^n$ that is free of restricted arithmetic progressions? We show that the ... more >>>


TR23-117 | 9th August 2023
François Le Gall, Yupan Liu, Qisheng Wang

Space-bounded quantum state testing via space-efficient quantum singular value transformation

Driven by exploring the power of quantum computation with a limited number of qubits, we present a novel complete characterization for space-bounded quantum computation, which encompasses settings with one-sided error (unitary coRQL) and two-sided error (BQL), approached from a quantum (mixed) state testing perspective:
- The first family of natural ... more >>>


TR23-118 | 17th August 2023
Hugo Aaronson, Tom Gur, Ninad Rajgopal, Ron Rothblum

Distribution-Free Proofs of Proximity

Revisions: 2

Motivated by the fact that input distributions are often unknown in advance, distribution-free property testing considers a setting in which the algorithmic task is to accept functions $f : [n] \to \{0,1\}$ having a certain property $\Pi$ and reject functions that are $\varepsilon$-far from $\Pi$, where the distance is measured ... more >>>


TR23-119 | 18th August 2023
Yotam Dikstein, Irit Dinur

Agreement theorems for high dimensional expanders in the small soundness regime: the role of covers

Given a family X of subsets of [n] and an ensemble of local functions $\{f_s:s\to\Sigma \;|\; s\in X\}$, an agreement test is a randomized property tester that is supposed to test whether there is some global function $G:[n]\to\Sigma$ such that $f_s=G|_s$ for many sets $s$. For example, the V-test chooses ... more >>>


TR23-120 | 18th August 2023
Mitali Bafna, Dor Minzer

Characterizing Direct Product Testing via Coboundary Expansion

A $d$-dimensional simplicial complex $X$ is said to support a direct product tester if any locally consistent function defined on its $k$-faces (where $k\ll d$) necessarily come from a function over its vertices. More precisely, a direct product tester has a distribution $\mu$ over pairs of $k$-faces $(A,A')$, and given ... more >>>


TR23-121 | 19th August 2023
Theodoros Papamakarios

Depth d Frege systems are not automatable unless P=NP

Revisions: 1

We show that for any integer $d>0$, depth $d$ Frege systems are NP-hard to automate. Namely, given a set $S$ of depth $d$ formulas, it is NP-hard to find a depth $d$ Frege refutation of $S$ in time polynomial in the size of the shortest such a refutation. This extends ... more >>>


TR23-122 | 9th August 2023
Vikraman Arvind, Abhranil Chatterjee

On Lifting Lower Bounds for Noncommutative Circuits using Automata

We revisit the main result of Carmosino et al \cite{CILM18} which shows that an $\Omega(n^{\omega/2+\epsilon})$ size noncommutative arithmetic circuit size lower bound (where $\omega$ is the matrix multiplication exponent) for a constant-degree $n$-variate polynomial family $(g_n)_n$, where each $g_n$ is a noncommutative polynomial, can be ``lifted'' to an exponential size ... more >>>


TR23-123 | 21st August 2023
Noam Mazor

Key-Agreement with Perfect Completeness from Random Oracles

In the Random Oracle Model (ROM) all parties have oracle access to a common random function, and the parties are limited in the number of queries they can make to the oracle. The Merkle’s Puzzles protocol, introduced by Merkle [CACM ’78], is a key-agreement protocol in the ROM with a ... more >>>


TR23-124 | 24th August 2023
Zander Kelley, Shachar Lovett, Raghu Meka

Explicit separations between randomized and deterministic Number-on-Forehead communication

Revisions: 1

We study the power of randomness in the Number-on-Forehead (NOF) model in communication complexity. We construct an explicit 3-player function $f:[N]^3 \to \{0,1\}$, such that: (i) there exist a randomized NOF protocol computing it that sends a constant number of bits; but (ii) any deterministic or nondeterministic NOF protocol computing ... more >>>


TR23-125 | 25th August 2023
Omar Alrabiah, Venkatesan Guruswami, Ray Li

Randomly punctured Reed-Solomon codes achieve list-decoding capacity over linear-sized fields

Reed-Solomon codes are a classic family of error-correcting codes consisting of evaluations of low-degree polynomials over a finite field on some sequence of distinct field elements. They are widely known for their optimal unique-decoding capabilities, but their list-decoding capabilities are not fully understood. Given the prevalence of Reed-Solomon codes, a ... more >>>


TR23-126 | 25th August 2023
Omar Alrabiah, Venkatesan Guruswami, Ray Li

AG codes have no list-decoding friends: Approaching the generalized Singleton bound requires exponential alphabets

A simple, recently observed generalization of the classical Singleton bound to list-decoding asserts that rate $R$ codes are not list-decodable using list-size $L$ beyond an error fraction $\frac{L}{L+1} (1-R)$ (the Singleton bound being the case of $L=1$, i.e., unique decoding). We prove that in order to approach this bound for ... more >>>


TR23-127 | 30th August 2023
Irit Dinur, Siqi Liu, Rachel Zhang

New Codes on High Dimensional Expanders

We describe a new family of symmetric error-correcting codes with low-density parity-check matrices (LDPC).

Our codes can be described in two seemingly different ways. First, in relation to Reed-Muller codes: our codes are functions on a subset of $\mathbb{F}^n$ whose restrictions to a prescribed set of affine lines has low ... more >>>


TR23-128 | 30th August 2023
Xue Chen, Kuan Cheng, Xin Li, Songtao Mao

Random Shortening of Linear Codes and Application

Random linear codes (RLCs) are well known to have nice combinatorial properties and near-optimal parameters in many different settings. However, getting explicit constructions matching the parameters of RLCs is challenging, and RLCs are hard to decode efficiently. This motivated several previous works to study the problem of partially derandomizing RLCs, ... more >>>


TR23-129 | 21st August 2023
Sravanthi Chede, Leroy Chew, Balesh Kumar, Anil Shukla

Understanding Nullstellensatz for QBFs

QBF proof systems are routinely adapted from propositional logic along with adjustments for the new quantifications. Existing are two main successful frameworks, the reduction and expansion frameworks, inspired by QCDCL [Zhang et al. ICCAD.'2002] and CEGAR solving [Janota et al. Artif. Intell.'2016] respectively. However, the reduction framework, while immensely useful ... more >>>


TR23-130 | 8th September 2023
Eshan Chattopadhyay, Jyun-Jie Liao

Recursive Error Reduction for Regular Branching Programs

Revisions: 1

In a recent work, Chen, Hoza, Lyu, Tal and Wu (FOCS 2023) showed an improved error reduction framework for the derandomization of regular read-once branching programs (ROBPs). Their result is based on a clever modification to the inverse Laplacian perspective of space-bounded derandomization, which was originally introduced by Ahmadinejad, Kelner, ... more >>>


TR23-131 | 8th September 2023
Meghal Gupta, Rachel Zhang

On Interactive Coding Schemes with Adaptive Termination

In interactive coding, Alice and Bob wish to compute some function $f$ of their individual private inputs $x$ and $y$. They do this by engaging in an interactive protocol to jointly compute $f(x,y)$. The goal is to do this in an error-resilient way, such that even given some fraction of ... more >>>


TR23-132 | 12th September 2023
Yogesh Dahiya, Meena Mahajan, Sasank Mouli

New lower bounds for Polynomial Calculus over non-Boolean bases


In this paper, we obtain new size lower bounds for proofs in the
Polynomial Calculus (PC) proof system, in two different settings.

1. When the Boolean variables are encoded using $\pm 1$ (as opposed
to $0,1$): We establish a lifting theorem using an asymmetric gadget
$G$, showing ... more >>>


TR23-133 | 13th September 2023
David Ellis, Guy Kindler, Noam Lifshitz, Dor Minzer

Product mixing in compact Lie groups

Revisions: 2

If $G$ is a group, we say a subset $S$ of $G$ is product-free if the equation $xy=z$ has no solutions with $x,y,z \in S$. For $D \in \mathbb{N}$, a group $G$ is said to be $D$-quasirandom if the minimal dimension of a nontrivial complex irreducible representation of $G$ is ... more >>>


TR23-134 | 14th September 2023
Oded Goldreich

On the complexity of enumerating ordered sets

We consider the complexity of enumerating ordered sets, defined as solving the following type of a computational problem: For a predetermined ordered set, given $i\in\N$, one is required to answer with the $i^{th}$ member of the set (according to the predetermined order).

Our focus is on countable sets such as ... more >>>


TR23-135 | 14th September 2023
Prerona Chatterjee, Anamay Tengse

On Annihilators of Explicit Polynomial Maps

We study the algebraic complexity of annihilators of polynomials maps. In particular, when a polynomial map is `encoded by' a small algebraic circuit, we show that the coefficients of an annihilator of the map can be computed in PSPACE. Even when the underlying field is that of reals or complex ... more >>>


TR23-136 | 14th September 2023
Benny Applebaum, Oded Nir

Advisor-Verifier-Prover Games and the Hardness of Information Theoretic Cryptography

A major open problem in information-theoretic cryptography is to obtain a super-polynomial lower bound for the communication complexity of basic cryptographic tasks. This question is wide open even for very powerful non-interactive primitives such as private information retrieval (or locally-decodable codes), general secret sharing schemes, conditional disclosure of secrets, and ... more >>>


TR23-137 | 10th September 2023
Mi-Ying Huang, Xinyu Mao, Guangxu Yang, Jiapeng Zhang

Communication Lower Bounds of Key-Agreement Protocols via Density Increment Arguments

Constructing key-agreement protocols in the random oracle model (ROM) is a viable method to assess the feasibility of developing public-key cryptography within Minicrypt. Unfortunately, as shown by Impagliazzo and Rudich (STOC 1989) and Barak and Mahmoody (Crypto 2009), such protocols can only guarantee limited security: any $\ell$-query protocol can be ... more >>>


TR23-138 | 12th September 2023
Lianna Hambardzumyan, Toniann Pitassi, Suhail Sherif, Morgan Shirley, Adi Shraibman

An improved protocol for ExactlyN with more than 3 players

The ExactlyN problem in the number-on-forehead (NOF) communication setting asks $k$ players, each of whom can see every input but their own, if the $k$ input numbers add up to $N$. Introduced by Chandra, Furst and Lipton in 1983, ExactlyN is important for its role in understanding the strength of ... more >>>


TR23-139 | 18th September 2023
Mrinal Kumar, Varun Ramanathan, Ramprasad Saptharishi

Deterministic Algorithms for Low Degree Factors of Constant Depth Circuits

For every constant $d$, we design a subexponential time deterministic algorithm that takes as input a multivariate polynomial $f$ given as a constant depth algebraic circuit over the field of rational numbers, and outputs all irreducible factors of $f$ of degree at most $d$ together with their respective multiplicities. Moreover, ... more >>>


TR23-140 | 20th September 2023
Eshan Chattopadhyay, Jesse Goodman, Mohit Gurumukhani

Extractors for Polynomial Sources over $\mathbb{F}_2$

Revisions: 1

We explicitly construct the first nontrivial extractors for degree $d \ge 2$ polynomial sources over $\mathbb{F}_2^n$. Our extractor requires min-entropy $k\geq n - \frac{\sqrt{\log n}}{(d\log \log n)^{d/2}}$. Previously, no constructions were known, even for min-entropy $k\geq n-1$. A key ingredient in our construction is an input reduction lemma, which allows ... more >>>


TR23-141 | 19th September 2023
Nader Bshouty, Gergely Harcos

A Tight Lower Bound of $\Omega(\log n)$ for the Estimation of the Number of Defective Items

Let $X$ be a set of items of size $n$ , which may contain some defective items denoted by $I$, where $I \subseteq X$. In group testing, a {\it test} refers to a subset of items $Q \subset X$. The test outcome is $1$ (positive) if $Q$ contains at least ... more >>>


TR23-142 | 21st September 2023
Tom Gur, Wilfred Salmon, Sergii Strelchuk

Provable Advantage in Quantum PAC Learning

We revisit the problem of characterising the complexity of Quantum PAC learning, as introduced by Bshouty and Jackson [SIAM J. Comput.
1998, 28, 1136–1153]. Several quantum advantages have been demonstrated in this setting, however, none are generic: they apply to particular concept classes and typically only work when the distribution ... more >>>


TR23-143 | 22nd September 2023
Noam Mazor, Rafael Pass

Counting Unpredictable Bits: A Simple PRG from One-way Functions

Revisions: 1

A central result in the theory of Cryptography, by Hastad, Imagliazzo, Luby and Levin [SICOMP’99], demonstrates that the existence one-way functions (OWF) implies the existence of pseudo-random generators (PRGs). Despite the fundamental importance of this result, and several elegant improvements/simplifications, analyses of constructions of PRGs from OWFs remain complex (both ... more >>>


TR23-144 | 22nd September 2023
Lijie Chen, Shuichi Hirahara, Hanlin Ren

Symmetric Exponential Time Requires Near-Maximum Circuit Size

We show that there is a language in $\mathrm{S}_2\mathrm{E}/_1$ (symmetric exponential time with one bit of advice) with circuit complexity at least $2^n/n$. In particular, the above also implies the same near-maximum circuit lower bounds for the classes $\Sigma_2\mathrm{E}$, $(\Sigma_2\mathrm{E}\cap\Pi_2\mathrm{E})/_1$, and $\mathrm{ZPE}^{\mathrm{NP}}/_1$. Previously, only "half-exponential" circuit lower bounds for these ... more >>>


TR23-145 | 20th September 2023
Arnab Bhattacharyya, Sutanu Gayen, Kuldeep S. Meel, Dimitrios Myrisiotis, A. Pavan, N. V. Vinodchandran

Total Variation Distance Estimation Is as Easy as Probabilistic Inference

In this paper, we establish a novel connection between total variation (TV) distance estimation and probabilistic inference. In particular, we present an efficient, structure-preserving reduction from relative approximation of TV distance to probabilistic inference over directed graphical models. This reduction leads to a fully polynomial randomized approximation scheme (FPRAS) for ... more >>>


TR23-146 | 27th September 2023
Oded Goldreich, Laliv Tauber

On Testing Isomorphism to a Fixed Graph in the Bounded-Degree Graph Model

Revisions: 1

We consider the problem of testing isomorphism to a fixed graph in the bounded-degree graph model. Our main result is that, for almost all $d$-regular $n$-vertex graphs $H$,
testing isomorphism to $H$ can be done using $\tildeO({\sqrt n})$ queries.
This result is shown to be optimal (up to ... more >>>


TR23-147 | 27th September 2023
Vikraman Arvind, Abhranil Chatterjee, Partha Mukhopadhyay

Black-Box Identity Testing of Noncommutative Rational Formulas in Deterministic Quasipolynomial Time

Revisions: 5 , Comments: 1

Rational Identity Testing (RIT) is the decision problem of determining whether or not a given noncommutative rational formula computes zero in the free skew field. It admits a deterministic polynomial-time white-box algorithm [Garg et al., 2016; Ivanyos et al., 2018; Hamada and Hirai, 2021], and a randomized polynomial-time black-box algorithm ... more >>>


TR23-148 | 3rd October 2023
Srinivasan Arunachalam, Uma Girish, Noam Lifshitz

One Clean Qubit Suffices for Quantum Communication Advantage

We study the one-clean-qubit model of quantum communication where one qubit is in a pure state and all other qubits are maximally mixed. We demonstrate a partial function that has a quantum protocol of cost $O(\log N)$ in this model, however, every interactive randomized protocol has cost $\Omega(\sqrt{N})$, settling a ... more >>>


TR23-149 | 5th October 2023
Ronen Shaltiel, Jad Silbak

Explicit Codes for Poly-Size Circuits and Functions that are Hard to Sample on Low Entropy Distributions

Revisions: 1

Guruswami and Smith (J. ACM 2016) considered codes for channels that are poly-size circuits which modify at most a $p$-fraction of the bits of the codeword. This class of channels is significantly stronger than Shannon's binary symmetric channel (BSC), but weaker than Hamming's channels which are computationally unbounded.

The goal ... more >>>


TR23-150 | 5th October 2023
Prerona Chatterjee, Kshitij Gajjar, Anamay Tengse

Monotone Classes Beyond VNP

In this work, we study the natural monotone analogues of various equivalent definitions of VPSPACE: a well studied class (Poizat 2008, Koiran & Perifel 2009, Malod 2011, Mahajan & Rao 2013) that is believed to be larger than VNP. We observe that these monotone analogues are not equivalent unlike their ... more >>>


TR23-151 | 11th October 2023
Hao Wu

An Improved Composition Theorem of a Universal Relation and Most Functions via Effective Restriction

Revisions: 1

One of the major open problems in complexity theory is to demonstrate an explicit function which requires super logarithmic depth, to tackle this problem Karchmer, Raz and Wigderson proposed the KRW conjecture about composition of two functions. While this conjecture seems out of our current reach, some relaxed conjectures are ... more >>>


TR23-152 | 14th October 2023
Yanyi Liu, Rafael Pass

One-way Functions and Hardness of (Probabilistic) Time-Bounded Kolmogorov Complexity w.r.t. Samplable Distributions

Consider the recently introduced notion of \emph{probabilistic
time-bounded Kolmogorov Complexity}, pK^t (Goldberg et al,
CCC'22), and let MpK^tP denote the language of pairs (x,k) such that pK^t(x) \leq k.
We show the equivalence of the following:
- MpK^{poly}P is (mildly) hard-on-average w.r.t. \emph{any} samplable
distribution $\D$;
- ... more >>>


TR23-153 | 19th October 2023
Natalia Dobrokhotova-Maikova, Alexander Kozachinskiy, Vladimir Podolskii

Towards Simpler Sorting Networks and Monotone Circuits for Majority

In this paper, we study the problem of computing the majority function by low-depth monotone circuits and a related problem of constructing low-depth sorting networks. We consider both the classical setting with elementary operations of arity $2$ and the generalized setting with operations of arity $k$, where $k$ is a ... more >>>


TR23-154 | 12th October 2023
Vishnu Iyer, Siddhartha Jain, Matt Kovacs-Deak, Vinayak Kumar, Luke Schaeffer, Daochen Wang, Michael Whitmeyer

On the Rational Degree of Boolean Functions and Applications

We study a natural complexity measure of Boolean functions known as the (exact) rational degree. For total functions $f$, it is conjectured that $\mathrm{rdeg}(f)$ is polynomially related to $\mathrm{deg}(f)$, where $\mathrm{deg}(f)$ is the Fourier degree. Towards this conjecture, we show that symmetric functions have rational degree at least $\mathrm{deg}(f)/2$ and ... more >>>


TR23-155 | 25th October 2023
Venkatesan Guruswami, Xuandi Ren, Sai Sandeep

Baby PIH: Parameterized Inapproximability of Min CSP

The Parameterized Inapproximability Hypothesis (PIH) is the analog of the PCP theorem in the world of parameterized complexity. It asserts that no FPT algorithm can distinguish a satisfiable 2CSP instance from one which is only $(1-\varepsilon)$-satisfiable (where the parameter is the number of variables) for some constant $0<\varepsilon<1$.

We ... more >>>


TR23-156 | 26th October 2023
Zeyong Li

Symmetric Exponential Time Requires Near-Maximum Circuit Size: Simplified, Truly Uniform

In a recent breakthrough, Chen, Hirahara and Ren prove that S$_2$E/$_1 \not\subset$ SIZE$[2^n/n]$ by giving a single-valued FS$_2$P algorithm for the Range Avoidance Problem (Avoid) that works for infinitely many input size $n$.

Building on their work, we present a simple single-valued FS$_2$P algorithm for Avoid that works for all ... more >>>


TR23-157 | 31st October 2023
Vladimir Podolskii, Dmitrii Sluch

One-Way Communication Complexity of Partial XOR Functions

Boolean function $F(x,y)$ for $x,y \in \{0,1\}^n$ is an XOR function if $F(x,y) = f(x\oplus y)$ for some function $f$ on $n$ input bits, where $\oplus$ is a bit-wise XOR. XOR functions are relevant in communication complexity, partially for allowing Fourier analytic technique. For total XOR functions it is known ... more >>>


TR23-158 | 1st November 2023
Oded Goldreich

On coarse and fine approximate counting of $t$-cliques

For any fixed $t$, we present two fine-grained reductions of the problem of approximately counting the number of $t$-cliques in a graph to the problem of detecting a $t$-clique in a graph.
One of our reductions is slightly better than the prior reduction of Dell, Lapinskas, and Meeks (SODA20) and ... more >>>


TR23-159 | 31st October 2023
Guangxu Yang, Jiapeng Zhang

Communication Lower Bounds for Collision Problems via Density Increment Arguments

Collision problems are important problems in complexity theory and cryptography with diverse applications. Previous fruitful works have mainly focused on query models. Driven by various applications, several works by Bauer, Farshim and Mazaheri (CRYPTO 2018), Itsykson and Riazanov (CCC 2021), Göös and Jain (RANDOM 2022) independently proposed the communication version ... more >>>


TR23-160 | 29th October 2023
Swastik Kopparty, Noga Ron-Zewi, Shubhangi Saraf

Simple Constructions of Unique Neighbor Expanders from Error-correcting Codes

Revisions: 1

In this note, we give very simple constructions of unique neighbor expander graphs starting from spectral or combinatorial expander graphs of mild expansion. These constructions and their analysis are simple variants of the constructions of LDPC error-correcting codes from expanders, given by
Sipser-Spielman~\cite{SS96} (and Tanner~\cite{Tanner81}), and their analysis. We also ... more >>>


TR23-161 | 1st November 2023
Tal Herman, Guy Rothblum

Doubly-Efficient Interactive Proofs for Distribution Properties

Suppose we have access to a small number of samples from an unknown distribution, and would like learn facts about the distribution.
An untrusted data server claims to have studied the distribution and makes assertions about its properties. Can the untrusted data server prove that its assertions are approximately correct? ... more >>>


TR23-162 | 1st November 2023
Pravesh Kothari, Peter Manohar

An Exponential Lower Bound for Linear 3-Query Locally Correctable Codes

We prove that the blocklength $n$ of a linear $3$-query locally correctable code (LCC) $\mathcal{L} \colon \mathbb{F}^k \to \mathbb{F}^n$ with distance $\delta$ must be at least $n \geq 2^{\Omega\left(\left(\frac{\delta^2 k}{(|\mathbb{F}|-1)^2}\right)^{1/8}\right)}$. In particular, the blocklength of a linear $3$-query LCC with constant distance over any small field grows exponentially with $k$. ... more >>>


TR23-163 | 30th October 2023
Nikhil Balaji, Samir Datta

USSR is in P/poly

The Sum of Square Roots (SSR) problem is the following computational problem: Given positive integers $a_1, \dots, a_k$, and signs $\delta_1, \dots, \delta_k \in \{-1, 1\}$, check if $\sum_{i=1}^k \delta_i \sqrt{a_i} > 0$. The problem is known to have a polynomial time algorithm on the real RAM model of computation, ... more >>>


TR23-164 | 5th November 2023
Shuo Wang, Guangxu Yang, Jiapeng Zhang

Communication Complexity of Set-Intersection Problems and Its Applications

Set-disjointness is one of the most fundamental and widely studied problems in the area of communication complexity. In this problem, each party $i$ receives a set $S_i\subseteq [N]$. The goal is to determine whether $\bigcap S_i$ is empty via communication between players. The decision version simply asks if the common ... more >>>


TR23-165 | 5th November 2023
Rahul Ilango

SAT Reduces to the Minimum Circuit Size Problem with a Random Oracle

The Minimum Circuit Size Problem (MCSP) asks, given the truth table of a Boolean function $f$ and an integer $s$, if there is a circuit computing $f$ of size at most $s.$ It has been an open question since Levin's seminal work on NP-completeness whether MCSP is NP-complete. This question ... more >>>


TR23-166 | 5th November 2023
Dmytro Gavinsky

Patterned non-determinism in communication complexity

We define and study the model of patterned non-determinism in bipartite communication complexity, denoted by $PNP^{X\leftrightarrow Y}$.
It generalises the known models $UP^{X\leftrightarrow Y}$ and $FewP^{X\leftrightarrow Y}$ through relaxing the constraints on the witnessing structure of the underlying $NP^{X\leftrightarrow Y}$-protocol.
It is shown that for the case of total functions ... more >>>


TR23-167 | 13th November 2023
Marshall Ball, Ronen Shaltiel, Jad Silbak

Non-malleable codes with optimal rate for poly-size circuits

We give an explicit construction of non-malleable codes with rate $1-o(1)$ for the tampering class of poly-size circuits. This rate is optimal, and improves upon the previous explicit construction of Ball, Dachman-Soled and Loss (CRYPTO 2022) which achieves a rate smaller than $\frac{1}{n}$. Our codes are based on the same ... more >>>


TR23-168 | 13th November 2023
Edward Pyne

Time-Space Tradeoffs for BPL via Catalytic Computation

Revisions: 1

We prove that for every $\alpha \in [1,1.5]$,
$$
\text{BPSPACE}[S]\subseteq \text{TISP}[2^{S^{\alpha}},S^{3-\alpha}]
$$
where $\text{BPSPACE}[S]$ corresponds to randomized space $O(S)$ computation, and $\text{TISP}[T,S]$ to time $poly(T)$, space $O(S)$ computation. Our result smoothly interpolates between the results of (Nisan STOC 1992) and (Saks and Zhou FOCS 1995), which prove $\text{BPSPACE}[S]$ is contained ... more >>>


TR23-169 | 14th November 2023
Marshall Ball, Dana Dachman-Soled, Eli Goldin, Saachi Mutreja

Extracting Randomness from Samplable Distributions, Revisited

Randomness extractors provide a generic way of converting sources of randomness that are
merely unpredictable into almost uniformly random bits. While in general, deterministic randomness
extraction is impossible, it is possible if the source has some structural constraints.
While much of the literature on deterministic extraction has focused on sources ... more >>>


TR23-170 | 13th November 2023
Pritam Chandra, Ankit Garg, Neeraj Kayal, Kunal Mittal, Tanmay Sinha

Learning Arithmetic Formulas in the Presence of Noise: A General Framework and Applications to Unsupervised Learning

We present a general framework for designing efficient algorithms for unsupervised learning problems, such as mixtures of Gaussians and subspace clustering. Our framework is based on a meta algorithm that learns arithmetic circuits in the presence of noise, using lower bounds. This builds upon the recent work of Garg, Kayal ... more >>>


TR23-171 | 15th November 2023
Shuichi Hirahara, Rahul Ilango, Ryan Williams

Beating Brute Force for Compression Problems

A compression problem is defined with respect to an efficient encoding function $f$; given a string $x$, our task is to find the shortest $y$ such that $f(y) = x$. The obvious brute-force algorithm for solving this compression task on $n$-bit strings runs in time $O(2^{\ell} \cdot t(n))$, where $\ell$ ... more >>>


TR23-172 | 14th November 2023
Meghal Gupta

Constant Query Local Decoding Against Deletions Is Impossible

Locally decodable codes (LDC's) are error-correcting codes that allow recovery of individual message indices by accessing only a constant number of codeword indices. For substitution errors, it is evident that LDC's exist -- Hadamard codes are examples of $2$-query LDC's. Research on this front has focused on finding the optimal ... more >>>


TR23-173 | 15th November 2023
Louis Golowich, Venkatesan Guruswami

Quantum Locally Recoverable Codes

Classical locally recoverable codes, which permit highly efficient recovery from localized errors as well as global recovery from larger errors, provide some of the most useful codes for distributed data storage in practice. In this paper, we initiate the study of quantum locally recoverable codes (qLRCs). In the long ... more >>>


TR23-174 | 15th November 2023
James Cook, Ian Mertz

Tree Evaluation is in Space O(log n · log log n)

The Tree Evaluation Problem ($TreeEval$) (Cook et al. 2009) is a central candidate for separating polynomial time ($P$) from logarithmic space ($L$) via composition. While space lower bounds of $\Omega(\log^2 n)$ are known for multiple restricted models, it was recently shown by Cook and Mertz (2020) that TreeEval can be ... more >>>


TR23-175 | 15th November 2023
Noam Mazor, Rafael Pass

The Non-Uniform Perebor Conjecture for Time-Bounded Kolmogorov Complexity is False

The Perebor (Russian for “brute-force search”) conjectures, which date back to the 1950s and 1960s are some of the oldest conjectures in complexity theory. The conjectures are a stronger form of the NP ? = P conjecture (which they predate) and state that for “meta-complexity” problems, such as the Time-bounded ... more >>>


TR23-176 | 15th November 2023
William Hoza

A Technique for Hardness Amplification Against $\mathrm{AC}^0$

Revisions: 1

We study hardness amplification in the context of two well-known "moderate" average-case hardness results for $\mathrm{AC}^0$ circuits. First, we investigate the extent to which $\mathrm{AC}^0$ circuits of depth $d$ can approximate $\mathrm{AC}^0$ circuits of some larger depth $d + k$. The case $k = 1$ is resolved by Håstad, Rossman, ... more >>>


TR23-177 | 18th November 2023
Kiran Kedlaya, Swastik Kopparty

On the degree of polynomials computing square roots mod p

Revisions: 1

For an odd prime $p$, we say $f(X) \in {\mathbb F}_p[X]$ computes square roots in $\mathbb F_p$ if, for all nonzero perfect squares $a \in \mathbb F_p$, we have $f(a)^2 = a$.

When $p \equiv 3$ mod $4$, it is well known that $f(X) = X^{(p+1)/4}$ computes square ... more >>>


TR23-178 | 16th November 2023
Louis Golowich, Tali Kaufman

NLTS Hamiltonians and Strongly-Explicit SoS Lower Bounds from Low-Rate Quantum LDPC Codes

Recent constructions of the first asymptotically good quantum LDPC (qLDPC) codes led to two breakthroughs in complexity theory: the NLTS (No Low-Energy Trivial States) theorem (Anshu, Breuckmann, and Nirkhe, STOC'23), and explicit lower bounds against a linear number of levels of the Sum-of-Squares (SoS) hierarchy (Hopkins and Lin, FOCS'22).

In ... more >>>


TR23-179 | 18th November 2023
Ian Mertz

Reusing Space: Techniques and Open Problems

In the world of space-bounded complexity, there is a strain of results showing that space can, somewhat paradoxically, be used for multiple purposes at once. Touchstone results include Barrington’s Theorem and the recent line of work on catalytic computing. We refer to such techniques, in contrast to the usual notion ... more >>>


TR23-180 | 17th November 2023
Amir Abboud, Nick Fischer, Zander Kelley, Shachar Lovett, Raghu Meka

New Graph Decompositions and Combinatorial Boolean Matrix Multiplication Algorithms

We revisit the fundamental Boolean Matrix Multiplication (BMM) problem. With the invention of algebraic fast matrix multiplication over 50 years ago, it also became known that BMM can be solved in truly subcubic $O(n^\omega)$ time, where $\omega<3$; much work has gone into bringing $\omega$ closer to $2$. Since then, a ... more >>>


TR23-181 | 20th November 2023
Mika Göös, Ilan Newman, Artur Riazanov, Dmitry Sokolov

Hardness Condensation by Restriction

Can every $n$-bit boolean function with deterministic query complexity $k\ll n$ be restricted to $O(k)$ variables such that the query complexity remains $\Omega(k)$? That is, can query complexity be condensed via restriction? We study such hardness condensation questions in both query and communication complexity, proving two main results.

$\bullet~$ $\mathbf{Negative}$: ... more >>>


TR23-182 | 21st November 2023
Prahladh Harsha, Mrinal Kumar, Ramprasad Saptharishi, Madhu Sudan

An Improved Line-Point Low-Degree Test

We prove that the most natural low-degree test for polynomials over finite fields is ``robust'' in the high-error regime for linear-sized fields. Specifically we consider the ``local'' agreement of a function $f\colon \mathbb{F}_q^m \to \mathbb{F}_q$ from the space of degree-$d$ polynomials, i.e., the expected agreement of the function from univariate ... more >>>


TR23-183 | 24th November 2023
Gil Cohen, Itay Cohen, Gal Maor, Yuval Peled

Derandomized Squaring: An Analytical Insight into Its True Behavior

The notion of the derandomized square of two graphs, denoted as $G \circ H$, was introduced by Rozenman and Vadhan as they rederived Reingold's Theorem, $\mathbf{SL} = \mathbf{L}$. This pseudorandom primitive, closely related to the Zig-Zag product, plays a crucial role in recent advancements on space-bounded derandomization. For this and ... more >>>


TR23-184 | 22nd November 2023
Gabriel Bathie, Ryan Williams

Towards Stronger Depth Lower Bounds

A fundamental problem in circuit complexity is to find explicit functions that require large depth to compute. When considering the natural DeMorgan basis of $\{\text{OR},\text{AND}\}$, where negations incur no cost, the best known depth lower bounds for an explicit function in NP have the form $(3-o(1))\log_2 n$, established by H{\aa}stad ... more >>>


TR23-185 | 27th November 2023
Rohan Goyal, Prahladh Harsha, Mrinal Kumar, A. Shankar

Fast list-decoding of univariate multiplicity and folded Reed-Solomon codes

Revisions: 2

We show that the known list-decoding algorithms for univariate multiplicity and folded Reed-Solomon (FRS) codes can be made to run in nearly-linear time. This yields, to the best of our knowledge, the first known family of codes that can be decoded (and encoded) in nearly linear time, even as they ... more >>>


TR23-186 | 28th November 2023
Ce Jin, Ryan Williams, Nathaniel Young

A VLSI Circuit Model Accounting For Wire Delay

Given the need for ever higher performance, and the failure of CPUs to keep providing single-threaded performance gains, engineers are increasingly turning to highly-parallel custom VLSI chips to implement expensive computations. In VLSI design, the gates and wires of a logical circuit are placed on a 2-dimensional chip with a ... more >>>


TR23-187 | 27th November 2023
Klim Efremenko, Michal Garlik, Dmitry Itsykson

Lower bounds for regular resolution over parities

The proof system resolution over parities (Res($\oplus$)) operates with disjunctions of linear equations (linear clauses) over $\mathbb{F}_2$; it extends the resolution proof system by incorporating linear algebra over $\mathbb{F}_2$. Over the years, several exponential lower bounds on the size of tree-like Res($\oplus$) refutations have been established. However, proving a superpolynomial ... more >>>


TR23-188 | 28th November 2023
Venkatesan Guruswami, Bingkai Lin, Xuandi Ren, Yican Sun, Kewen Wu

Parameterized Inapproximability Hypothesis under ETH

The Parameterized Inapproximability Hypothesis (PIH) asserts that no fixed parameter tractable (FPT) algorithm can distinguish a satisfiable CSP instance, parameterized by the number of variables, from one where every assignment fails to satisfy an $\varepsilon$ fraction of constraints for some absolute constant $\varepsilon > 0$. PIH plays the role of ... more >>>


TR23-189 | 28th November 2023
John Kallaugher, Ojas Parekh, Nadezhda Voronova

Exponential Quantum Space Advantage for Approximating Maximum Directed Cut in the Streaming Model

While the search for quantum advantage typically focuses on speedups in execution time, quantum algorithms also offer the potential for advantage in space complexity. Previous work has shown such advantages for data stream problems, in which elements arrive and must be processed sequentially without random access, but these have been ... more >>>


TR23-190 | 15th November 2023
Leonid Gurvits, Nathan Klein, Jonathan Leake

From Trees to Polynomials and Back Again: New Capacity Bounds with Applications to TSP

We give simply exponential lower bounds on the probabilities of a given strongly Rayleigh distribution, depending only on its expectation. This resolves a weak version of a problem left open by Karlin-Klein-Oveis Gharan in their recent breakthrough work on metric TSP, and this resolution leads to a minor improvement of ... more >>>


TR23-191 | 2nd December 2023
Hervé Fournier, Nutan Limaye, Srikanth Srinivasan, Sébastien Tavenas

On the Power of Homogeneous Algebraic Formulas

Proving explicit lower bounds on the size of algebraic formulas is a long-standing open problem in the area of algebraic complexity theory. Recent results in the area (e.g. a lower bound against constant-depth algebraic formulas due to Limaye, Srinivasan, and Tavenas (FOCS 2021)) have indicated a way forward for attacking ... more >>>


TR23-192 | 28th November 2023
Noam Mazor, Rafael Pass

A Note On the Universality of Black-box MKtP Solvers

Revisions: 1

The relationships between various meta-complexity problems are not well understood in the worst-case regime, including whether the search version is harder than the decision version, whether the hardness scales with the ``threshold", and how the hardness of different meta-complexity problems relate to one another, and to the task of function ... more >>>


TR23-193 | 3rd December 2023
Eldon Chung, Alexander Golovnev, Zeyong Li, Maciej Obremski, Sidhant Saraogi, Noah Stephens-Davidowitz

On the randomized complexity of range avoidance, with applications to cryptography and metacomplexity

We study the Range Avoidance Problem (Avoid), in which the input is an expanding circuit $C : \{0,1\}^n \to \{0,1\}^{n+1}$, and the goal is to find a $y \in \{0,1\}^{n+1}$ that is not in the image of $C$. We are interested in the randomized complexity of this problem, i.e., in ... more >>>


TR23-194 | 5th December 2023
Siddharth Iyer, Anup Rao

XOR Lemmas for Communication via Marginal Information

We define the marginal information of a communication protocol, and use it to prove XOR lemmas for communication complexity. We show that if every $C$-bit protocol has bounded advantage for computing a Boolean function $f$, then every $\tilde \Omega(C \sqrt{n})$-bit protocol has advantage $\exp(-\Omega(n))$ for computing the $n$-fold xor $f^{\oplus ... more >>>


TR23-195 | 6th December 2023
Shai Evra, Shay Gadot, Ohad Klein, Ilan Komargodski

Verifying Groups in Linear Time

We consider the following problem: Given an $n \times n$ multiplication table, decide whether it is a Cayley multiplication table of a group. Among deterministic algorithms for this problem, the best known algorithm is implied by F. W. Light's associativity test (1949) and has running time of $O(n^2 \log n)$. ... more >>>


TR23-196 | 7th December 2023
Huacheng Yu, Wei Zhan

Sampling, Flowers and Communication

Given a distribution over $[n]^n$ such that any $k$ coordinates need $k/\log^{O(1)}n$ bits of communication to sample, we prove that any map that samples this distribution from uniform cells requires locality $\Omega(\log(n/k)/\log\log(n/k))$. In particular, we show that for any constant $\delta>0$, there exists $\varepsilon=2^{-\Omega(n^{1-\delta})}$ such that $\Omega(\log n/\log\log n)$ non-adaptive ... more >>>


TR23-197 | 7th December 2023
Sepehr Assadi, Gillat Kol, Zhijun Zhang

Optimal Multi-Pass Lower Bounds for MST in Dynamic Streams

The seminal work of Ahn, Guha, and McGregor in 2012 introduced the graph sketching technique and used it to present the first streaming algorithms for various graph problems over dynamic streams with both insertions and deletions of edges. This includes algorithms for cut sparsification, spanners, matchings, and minimum spanning trees ... more >>>


TR23-198 | 8th December 2023
Amey Bhangale, Mark Braverman, Subhash Khot, Yang P. Liu, Dor Minzer

Parallel Repetition of k-Player Projection Games

We study parallel repetition of k-player games where the constraints satisfy the projection property. We prove exponential decay in the value of a parallel repetition of projection games with value less than 1.

more >>>

TR23-199 | 9th December 2023
Ján Pich, Rahul Santhanam

Towards P $\neq$ NP from Extended Frege Lower Bounds

We give a new approach to the fundamental question of whether proof complexity lower bounds for concrete propositional proof systems imply super-polynomial Boolean circuit lower bounds.

For any poly-time computable function $f$, we define the witnessing formulas $w_n^k(f)$, which are propositional formulas stating that for any circuit $C$ of size ... more >>>


TR23-200 | 6th December 2023
Joseph Shunia

An Efficient Deterministic Primality Test

Revisions: 1 , Comments: 4

A deterministic primality test with a polynomial time complexity of $\tilde{O}(\log^3(n))$ is presented. The test posits that an integer $n$ satisfying the conditions of the main theorem is prime. Combining elements of number theory and combinatorics, the proof operates on the basis of simultaneous modular congruences relating to binomial transforms ... more >>>


TR23-201 | 16th October 2023
Alexander Shekhovtsov, Georgii Zakharov

Enumerating Complexity Revisited

We reduce the best-known upper bound on the length of a program that enumerates a set in terms of the probability of it being enumerated by a random program. We prove a general result that any linear upper bound for finite sets implies the same linear bound for infinite sets.

... more >>>

TR23-202 | 15th December 2023
C Ramya, Pratik Shastri

Lower Bounds for Planar Arithmetic Circuits

Arithmetic circuits are a natural well-studied model for computing multivariate polynomials over a field. In this paper, we study planar arithmetic circuits. These are circuits whose underlying graph is planar. In particular, we prove an $\Omega(n\log n)$ lower bound on the size of planar arithmetic circuits computing explicit bilinear forms ... more >>>


TR23-203 | 15th December 2023
Hamed Hatami, Kaave Hosseini, Shachar Lovett, Anthony Ostuni

Refuting approaches to the log-rank conjecture for XOR functions

The log-rank conjecture, a longstanding problem in communication complexity, has persistently eluded resolution for decades. Consequently, some recent efforts have focused on potential approaches for establishing the conjecture in the special case of XOR functions, where the communication matrix is lifted from a boolean function, and the rank of ... more >>>


TR23-204 | 17th November 2023
John Bostanci, Luowen Qian, Nicholas Spooner, Henry Yuen

An efficient quantum parallel repetition theorem and applications

We prove a tight parallel repetition theorem for 3-message computationally-secure quantum interactive protocols between an efficient challenger and an efficient adversary. We also prove under plausible assumptions that the security of 4-message computationally secure protocols does not generally decrease under parallel repetition. These mirror the classical results of Bellare, Impagliazzo, ... more >>>


TR23-205 | 21st December 2023
Marshall Ball, Dana Dachman-Soled

(Inefficient Prover) ZAPs from Hard-to-Invert Functions

A ZAP is a witness-indistinguishable two-message public-coin interactive proof with the following simple structure: the verifier sends a uniformly random string, the prover responds, and the verifier decides in polynomial time whether to accept or reject.

We show that one-way functions imply the existence of ... more >>>


TR23-206 | 9th December 2023
Yilei Chen, Jiatu Li

Hardness of Range Avoidance and Remote Point for Restricted Circuits via Cryptography

A recent line of research has introduced a systematic approach to explore the complexity of explicit construction problems through the use of meta problems, namely, the range avoidance problem (abbrev. Avoid) and the remote point problem (abbrev. RPP). The upper and lower bounds for these meta problems provide a unified ... more >>>


TR23-207 | 13th December 2023
Omri Ben-Eliezer, Tomer Grossman, Moni Naor

Does Prior Knowledge Help Detect Collisions?

Suppose you are given a function $f\colon [n] \to [n]$ via (black-box) query access to the function. You are looking to find something local, like a collision (a pair $x \neq y$ s.t.\ $f(x)=f(y)$). The question is whether knowing the `shape' of the function helps you or not (by shape ... more >>>


TR23-208 | 21st December 2023
Dean Doron, Edward Pyne, Roei Tell

Opening Up the Distinguisher: A Hardness to Randomness Approach for BPL = L that Uses Properties of BPL

We provide compelling evidence for the potential of hardness-vs.-randomness approaches to make progress on the long-standing problem of derandomizing space-bounded computation.

Our first contribution is a derandomization of bounded-space machines from hardness assumptions for classes of uniform deterministic algorithms, for which strong (but non-matching) lower bounds can be unconditionally proved. ... more >>>


TR23-209 | 23rd December 2023
Yotam Dikstein, Irit Dinur

Swap cosystolic expansion

We introduce and study swap cosystolic expansion, a new expansion property of simplicial complexes. We prove lower bounds for swap coboundary expansion of spherical buildings and use them to lower bound swap cosystolic expansion of the LSV Ramanujan complexes. Our motivation is the recent work (in a companion paper) showing ... more >>>


TR23-210 | 22nd December 2023
Eshan Chattopadhyay, Mohit Gurumukhani, Noam Ringach

On the Existence of Seedless Condensers: Exploring the Terrain

While the existence of randomness extractors, both seeded and seedless, has been thoroughly studied for many sources of randomness, currently, very little is known regarding the existence of seedless condensers in many settings. Here, we prove several new results for seedless condensers in the context of three related classes of ... more >>>


TR23-211 | 23rd December 2023
Rafael Pass, Oren Renard

Characterizing the Power of (Persistent) Randomness in Log-space

We study the problem of whether \emph{persistent} randomness is helpful for polynomial-time algorithms that only use \emph{logarithmic} space. In more detail, we consider the class $\searchBPLs$, of \emph{search}-problems that are solvable by a polynomial-time Probabilistic Logspace TMs with \emph{2-way} access (i.e., with multiple, as opposed to one-time, access) to a ... more >>>


TR23-212 | 26th December 2023
Prerona Chatterjee, Deepanshu Kush, Shubhangi Saraf, Amir Shpilka

Exponential Lower Bounds Against Sums of ROABPs

Revisions: 2

In this paper, we prove the first super-polynomial and, in fact, exponential lower bound for the model of sum of read-once oblivious algebraic branching programs (ROABPs). In particular, we give an explicit polynomial such that any sum of ROABPs
(equivalently, sum of *ordered* set-multilinear branching programs, each with a ... more >>>


TR23-213 | 31st December 2023
Riddhi Ghosal, Yuval Ishai, Alexis Korb, Eyal Kushilevitz, Paul Lou, Amit Sahai

Hard Languages in $\text{NP}\cap\text{coNP}$ and NIZK Proofs from Unstructured Hardness

The existence of "unstructured" hard languages in $\text{NP}\cap\text{coNP}$ is an intriguing open question. Bennett and Gill (SICOMP, 1981) asked whether $\text{P}$ is separated from $\text{NP}\cap\text{coNP}$ relative to a random oracle, a question that remained open ever since. While a hard language in $\text{NP}\cap\text{coNP}$ can be constructed in a black-box way ... more >>>


TR23-214 | 31st December 2023
Oded Goldreich, Laliv Tauber

On Testing Group Properties

Revisions: 1

Following Ergun et al. (JCSS 2000), we consider testing group properties and focus on the problem of testing whether a binary operation is a group operation.
That is, given a finite set $S$ and oracle access to a function $f:S\times S \to S$, we wish to distinguish the case that ... more >>>




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