Under the auspices of the Computational Complexity Foundation (CCF)

REPORTS > 2012:
All reports in year 2012:
TR12-001 | 1st January 2012
Arnab Bhattacharyya, Eldar Fischer, Shachar Lovett

#### Testing Low Complexity Affine-Invariant Properties

Invariance with respect to linear or affine transformations of the domain is arguably the most common symmetry exhibited by natural algebraic properties. In this work, we show that any low complexity affine-invariant property of multivariate functions over finite fields is testable with a constant number of queries. This immediately reproves, ... more >>>

TR12-002 | 4th January 2012
Akinori Kawachi, Benjamin Rossman, Osamu Watanabe

#### Query Complexity and Error Tolerance of Witness Finding Algorithms

Revisions: 3

We propose an abstract framework for studying search-to-decision reductions for NP. Specifically, we study the following witness finding problem: for a hidden nonempty set $W\subseteq\{0,1\}^n$, the goal is to output a witness in $W$ with constant probability by making randomized queries of the form is $Q\cap W$ nonempty?''\ where $Q\subseteq\{0,1\}^n$. ... more >>>

TR12-003 | 13th December 2011
Pratik Worah

#### Rank Bounds for a Hierarchy of Lov\'{a}sz and Schrijver

Lov\'{a}sz and Schrijver introduced several lift and project methods for $0$-$1$ integer programs, now collectively known as Lov\'{a}sz-Schrijver ($LS$) hierarchies. Several lower bounds have since been proven for the rank of various linear programming relaxations in the $LS$ and $LS_+$ hierarchies. In this paper we investigate rank bounds in the ... more >>>

TR12-004 | 10th January 2012
Marcos Villagra, Masaki Nakanishi, Shigeru Yamashita, Yasuhiko Nakashima

#### Tensor Rank and Strong Quantum Nondeterminism in Multiparty Communication

Revisions: 3

In this paper we study quantum nondeterminism in multiparty communication. There are three (possibly) different types of nondeterminism in quantum computation: i) strong, ii) weak with classical proofs, and iii) weak with quantum proofs. Here we focus on the first one. A strong quantum nondeterministic protocol accepts a correct input ... more >>>

TR12-005 | 13th January 2012
Periklis Papakonstantinou, Guang Yang

#### A remark on one-wayness versus pseudorandomness

Every pseudorandom generator is in particular a one-way function. If we only consider part of the output of the
pseudorandom generator is this still one-way? Here is a general setting formalizing this question. Suppose
$G:\{0,1\}^n\rightarrow \{0,1\}^{\ell(n)}$ is a pseudorandom generator with stretch $\ell(n)> n$. Let $M_R\in\{0,1\}^{m(n)\times \ell(n)}$ be a linear ... more >>>

TR12-006 | 21st January 2012
Gregory Valiant

Revisions: 2

Given a set of $n$ random $d$-dimensional boolean vectors with the promise that two of them are $\rho$-correlated with each other, how quickly can one find the two correlated vectors? We present a surprising and simple algorithm which, for any constant $\epsilon>0$ runs in (expected) time $d n^{\frac{3 \omega}{4}+\epsilon} poly(\frac{1}{\rho})< ... more >>> TR12-007 | 28th January 2012 Ruiwen Chen, Valentine Kabanets #### Lower Bounds against Weakly Uniform Circuits Revisions: 1 A family of Boolean circuits$\{C_n\}_{n\geq 0}$is called \emph{$\gamma(n)$-weakly uniform} if there is a polynomial-time algorithm for deciding the direct-connection language of every$C_n$, given \emph{advice} of size$\gamma(n)$. This is a relaxation of the usual notion of uniformity, which allows one to interpolate between complete uniformity (when$\gamma(n)=0$) ... more >>> TR12-008 | 30th January 2012 Marek Karpinski, Richard Schmied #### On Approximation Lower Bounds for TSP with Bounded Metrics Revisions: 1 We develop a new method for proving explicit approximation lower bounds for TSP problems with bounded metrics improving on the best up to now known bounds. They almost match the best known bounds for unbounded metric TSP problems. In particular, we prove the best known lower bound for TSP with ... more >>> TR12-009 | 28th November 2011 Prabhu Manyem, Julien Ugon #### Computational Complexity, NP Completeness and Optimization Duality: A Survey We survey research that studies the connection between the computational complexity of optimization problems on the one hand, and the duality gap between the primal and dual optimization problems on the other. To our knowledge, this is the first survey that connects the two very important areas. We further look ... more >>> TR12-010 | 5th February 2012 Shafi Goldwasser, Guy Rothblum #### How to Compute in the Presence of Leakage We address the following problem: how to execute any algorithm P, for an unbounded number of executions, in the presence of an adversary who observes partial information on the internal state of the computation during executions. The security guarantee is that the adversary learns nothing, beyond P's input/output behavior. This ... more >>> TR12-011 | 7th February 2012 Nader Bshouty #### Testers and their Applications We develop a new notion called {\it tester of a class$\cM$of functions}$f:\cA\to \cC$that maps the elements$\bfa\in \cA$in the domain$\cA$of the function to a finite number (the size of the tester) of elements$\bfb_1,\ldots,\bfb_t$in a smaller sub-domain$\cB\subset \cA$where the property ... more >>> TR12-012 | 9th February 2012 Oded Goldreich #### On the Effect of the Proximity Parameter on Property Testers This note refers to the effect of the proximity parameter on the operation of (standard) property testers. Its bottom-line is that, except in pathological cases, the effect of the proximity parameter is restricted to determining the query complexity of the tester. The point is that, in non-pathological cases, the mapping ... more >>> TR12-013 | 15th February 2012 Tomas Feder, Carlos Subi #### Packing Edge-Disjoint Triangles in Given Graphs Given a graph$G$, we consider the problem of finding the largest set of edge-disjoint triangles contained in$G$. We show that even the simpler case of decomposing the edges of a sparse split graph$G$into edge-disjoint triangles is NP-complete. We show next that the case of a general ... more >>> TR12-014 | 20th February 2012 Johannes Mittmann, Nitin Saxena, Peter Scheiblechner #### Algebraic Independence in Positive Characteristic -- A p-Adic Calculus A set of multivariate polynomials, over a field of zero or large characteristic, can be tested for algebraic independence by the well-known Jacobian criterion. For fields of other characteristic$p>0$, there is no analogous characterization known. In this paper we give the first such criterion. Essentially, it boils down to ... more >>> TR12-015 | 22nd February 2012 Albert Atserias, Anuj Dawar #### Degree Lower Bounds of Tower-Type for Approximating Formulas with Parity Quantifiers Revisions: 2 Kolaitis and Kopparty have shown that for any first-order formula with parity quantifiers over the language of graphs there is a family of multi-variate polynomials of constant-degree that agree with the formula on all but a$2^{-\Omega(n)}$-fraction of the graphs with$n$vertices. The proof yields a bound on the ... more >>> TR12-016 | 24th February 2012 Anindya De, Elchanan Mossel #### Explicit Optimal hardness via Gaussian stability results Revisions: 3 The results of Raghavendra (2008) show that assuming Khot's Unique Games Conjecture (2002), for every constraint satisfaction problem there exists a generic semi-definite program that achieves the optimal approximation factor. This result is existential as it does not provide an explicit optimal rounding procedure nor does it allow to calculate ... more >>> TR12-017 | 1st March 2012 Venkatesan Guruswami, Srivatsan Narayanan #### Combinatorial limitations of a strong form of list decoding Revisions: 1 We prove the following results concerning the combinatorics of list decoding, motivated by the exponential gap between the known upper bound (of$O(1/\gamma)$) and lower bound (of$\Omega_p(\log (1/\gamma))$) for the list-size needed to decode up to radius$p$with rate$\gamma$away from capacity, i.e.,$1-h(p)-\gamma$(here$p\in (0,1/2)$... more >>> TR12-018 | 24th February 2012 Joerg Flum, Moritz Müller #### Some definitorial suggestions for parameterized proof complexity We introduce a (new) notion of parameterized proof system. For parameterized versions of standard proof systems such as Extended Frege and Substitution Frege we compare their complexity with respect to parameterized simulations. more >>> TR12-019 | 2nd March 2012 Eric Miles, Emanuele Viola #### On the complexity of constructing pseudorandom functions (especially when they don't exist) We study the complexity of black-box constructions of pseudorandom functions (PRF) from one-way functions (OWF) that are secure against non-uniform adversaries. We show that if OWF do not exist, then given as an oracle any (inefficient) hard-to-invert function, one can compute a PRF in polynomial time with only$k(n)$oracle ... more >>> TR12-020 | 3rd March 2012 Daniele Micciancio #### Inapproximability of the Shortest Vector Problem: Toward a Deterministic Reduction Revisions: 1 We prove that the Shortest Vector Problem (SVP) on point lattices is NP-hard to approximate for any constant factor under polynomial time reverse unfaithful random reductions. These are probabilistic reductions with one-sided error that produce false negatives with small probability, but are guaranteed not to produce false positives regardless of ... more >>> TR12-021 | 14th March 2012 Oded Goldreich, Igor Shinkar #### Two-Sided Error Proximity Oblivious Testing Revisions: 4 Loosely speaking, a proximity-oblivious (property) tester is a randomized algorithm that makes a constant number of queries to a tested object and distinguishes objects that have a predetermined property from those that lack it. Specifically, for some threshold probability$c$, objects having the property are accepted with probability at least ... more >>> TR12-022 | 14th March 2012 Amit Chakrabarti, Graham Cormode, Andrew McGregor, Justin Thaler #### Annotations in Data Streams Revisions: 1 The central goal of data stream algorithms is to process massive streams of data using sublinear storage space. Motivated by work in the database community on outsourcing database and data stream processing, we ask whether the space usage of such algorithms can be further reduced by enlisting a more powerful ... more >>> TR12-023 | 19th March 2012 Sophie Laplante, Virginie Lerays, Jérémie Roland #### Classical and quantum partition bound and detector inefficiency In communication complexity, two players each have an input and they wish to compute some function of the joint inputs. This has been the object of much study and a wide variety of lower bound methods have been introduced to address the problem of showing lower bounds on communication. Recently, ... more >>> TR12-024 | 25th March 2012 Scott Aaronson, Paul Christiano #### Quantum Money from Hidden Subspaces Forty years ago, Wiesner pointed out that quantum mechanics raises the striking possibility of money that cannot be counterfeited according to the laws of physics. We propose the first quantum money scheme that is (1) public-key, meaning that anyone can verify a banknote as genuine, not only the bank that ... more >>> TR12-025 | 23rd March 2012 Kord Eickmeyer, Kristoffer Arnsfelt Hansen, Elad Verbin #### Approximating the minmax value of 3-player games within a constant is as hard as detecting planted cliques We consider the problem of approximating the minmax value of a multiplayer game in strategic form. We argue that in 3-player games with 0-1 payoffs, approximating the minmax value within an additive constant smaller than$\xi/2$, where$\xi = \frac{3-\sqrt5}{2} \approx 0.382$, is not possible by a polynomial time algorithm. ... more >>> TR12-026 | 27th March 2012 Thomas Watson #### Time Hierarchies for Sampling Distributions Revisions: 2 We prove that for every constant$k\ge 2$, every polynomial time bound$t$, and every polynomially small$\epsilon$, there exists a family of distributions on$k$elements that can be sampled exactly in polynomial time but cannot be sampled within statistical distance$1-1/k-\epsilon$in time$t$. Our proof involves reducing ... more >>> TR12-027 | 29th March 2012 Eric Allender, Shiteng Chen, Tiancheng Lou, Periklis Papakonstantinou, Bangsheng Tang #### Time-space tradeoffs for width-parameterized SAT:Algorithms and lower bounds Revisions: 2 A decade has passed since Alekhnovich and Razborov presented an algorithm that solves SAT on instances$\phi$of size$n$having tree-width$TW(\phi)$, using time (and space) bounded by$2^{O(TW(\phi))}n^{O(1)}$. Although there have been several papers over the ensuing years building on the work of Alekhnovich and Razborov there has ... more >>> TR12-028 | 30th March 2012 Eric Allender, George Davie, Luke Friedman, Samuel Hopkins, Iddo Tzameret #### Kolmogorov Complexity, Circuits, and the Strength of Formal Theories of Arithmetic Revisions: 1 Can complexity classes be characterized in terms of efficient reducibility to the (undecidable) set of Kolmogorov-random strings? Although this might seem improbable, a series of papers has recently provided evidence that this may be the case. In particular, it is known that there is a class of problems$C$defined ... more >>> TR12-029 | 3rd April 2012 Shachar Lovett #### An exposition of Sanders quasi-polynomial Freiman-Ruzsa theorem The polynomial Freiman-Ruzsa conjecture is one of the important conjectures in additive combinatorics. It asserts than one can switch between combinatorial and algebraic notions of approximate subgroups with only a polynomial loss in the underlying parameters. This conjecture has also already found several applications in theoretical computer science. Recently, Tom ... more >>> TR12-030 | 4th April 2012 C. Seshadhri, Deeparnab Chakrabarty #### Optimal bounds for monotonicity and Lipschitz testing over the hypercube Revisions: 2 The problem of monotonicity testing of the boolean hypercube is a classic well-studied, yet unsolved question in property testing. We are given query access to$f:\{0,1\}^n \mapsto R$(for some ordered range$R$). The boolean hypercube${\cal B}^n$has a natural partial order, denoted by$\prec$(defined by the product ... more >>> TR12-031 | 4th April 2012 Tom Gur, Omer Tamuz #### Testing Booleanity and the Uncertainty Principle Revisions: 1 Let$f:\{-1,1\}^n \to \mathbb{R}$be a real function on the hypercube, given by its discrete Fourier expansion, or, equivalently, represented as a multilinear polynomial. We say that it is Boolean if its image is in$\{-1,1\}$. We show that every function on the hypercube with a ... more >>> TR12-032 | 4th April 2012 Sebastian Kuhnert, Johannes Köbler, Osamu Watanabe #### Interval graph representation with given interval and intersection lengths We consider the problem of finding interval representations of graphs that additionally respect given interval lengths and/or pairwise intersection lengths, which are represented as weight functions on the vertices and edges, respectively. Pe'er and Shamir proved that the problem is NP-complete if only the former are given [SIAM J. Discr. ... more >>> TR12-033 | 5th April 2012 Ankit Gupta, Neeraj Kayal, Youming Qiao #### Random Arithmetic Formulas can be Reconstructed Efficiently Informally stated, we present here a randomized algorithm that given blackbox access to the polynomial$f$computed by an unknown/hidden arithmetic formula$\phi$reconstructs, on the average, an equivalent or smaller formula$\hat{\phi}$in time polynomial in the size of its output$\hat{\phi}$. Specifically, we consider arithmetic formulas wherein the ... more >>> TR12-034 | 5th April 2012 Abhishek Bhowmick, Zeev Dvir, Shachar Lovett #### New Lower Bounds for Matching Vector Codes Revisions: 5 We prove new lower bounds on the encoding length of Matching Vector (MV) codes. These recently discovered families of Locally Decodable Codes (LDCs) originate in the works of Yekhanin [Yek] and Efremenko [Efr] and are the only known families of LDCs with a constant number of queries and sub-exponential encoding ... more >>> TR12-035 | 5th April 2012 Artur Czumaj, Oded Goldreich, Dana Ron, C. Seshadhri, Asaf Shapira, Christian Sohler #### Finding Cycles and Trees in Sublinear Time Revisions: 1 , Comments: 1 (This is a revised version of work that was posted on arXiv in July 2010.) We present sublinear-time (randomized) algorithms for finding simple cycles of length at least$k\geq3$and tree-minors in bounded-degree graphs. The complexity of these algorithms is related to the distance of the graph from being ... more >>> TR12-036 | 12th April 2012 Venkatesan Guruswami, Chaoping Xing #### Folded Codes from Function Field Towers and Improved Optimal Rate List Decoding We give a new construction of algebraic codes which are efficiently list decodable from a fraction$1-R-\epsilon$of adversarial errors where$R$is the rate of the code, for any desired positive constant$\epsilon$. The worst-case list size output by the algorithm is$O(1/\epsilon)$, matching the existential bound for random ... more >>> TR12-037 | 10th April 2012 Alexander A. Sherstov #### Making Polynomials Robust to Noise A basic question in any computational model is how to reliably compute a given function when the inputs or intermediate computations are subject to noise at a constant rate. Ideally, one would like to use at most a constant factor more resources compared to the noise-free case. This question has ... more >>> TR12-038 | 6th April 2012 Iordanis Kerenidis, Sophie Laplante, Virginie Lerays, Jérémie Roland, David Xiao #### Lower bounds on information complexity via zero-communication protocols and applications We show that almost all known lower bound methods for communication complexity are also lower bounds for the information complexity. In particular, we define a relaxed version of the partition bound of Jain and Klauck and prove that it lower bounds the information complexity of any function. Our relaxed partition ... more >>> TR12-039 | 17th April 2012 Stasys Jukna #### Clique Problem, Cutting Plane Proofs, and Communication Complexity Motivated by its relation to the length of cutting plane proofs for the Maximum Biclique problem, here we consider the following communication game on a given graph G, known to both players. Let K be the maximal number of vertices in a complete bipartite subgraph of G (which is not ... more >>> TR12-040 | 17th April 2012 Sangxia Huang #### Approximation Resistance on Satisfiable Instances for Predicates Strictly Dominating Parity In this paper, we study the approximability of Max CSP($P$) where$P$is a Boolean predicate. We prove that assuming Khot's$d$-to-1 Conjecture, if the set of accepting inputs of$P$strictly contains all inputs with even (or odd) parity, then it is NP-hard to approximate Max CSP($P$) better than ... more >>> TR12-041 | 17th April 2012 Stasys Jukna #### Limitations of Incremental Dynamic Programs Revisions: 1 We consider so-called incremental'' dynamic programming (DP) algorithms, and are interested in the number of subproblems produced by them. The standard DP algorithm for the n-dimensional Knapsack problem is incremental, and produces nK subproblems, where K is the capacity of the knapsack. We show that any incremental algorithm for this ... more >>> TR12-042 | 17th April 2012 Chris Beck, Russell Impagliazzo, Shachar Lovett #### Large Deviation Bounds for Decision Trees and Sampling Lower Bounds for AC0-circuits There has been considerable interest lately in the complexity of distributions. Recently, Lovett and Viola (CCC 2011) showed that the statistical distance between a uniform distribution over a good code, and any distribution which can be efficiently sampled by a small bounded-depth AC0 circuit, is inverse-polynomially close to one. That ... more >>> TR12-043 | 16th April 2012 Zvika Brakerski, Yael Tauman Kalai #### Efficient Interactive Coding Against Adversarial Noise Revisions: 1 In this work, we study the fundamental problem of constructing interactive protocols that are robust to noise, a problem that was originally considered in the seminal works of Schulman (FOCS '92, STOC '93), and has recently regained popularity. Robust interactive communication is the interactive analogue of error correcting codes: Given ... more >>> TR12-044 | 22nd April 2012 Swastik Kopparty #### List-Decoding Multiplicity Codes We study the list-decodability of multiplicity codes. These codes, which are based on evaluations of high-degree polynomials and their derivatives, have rate approaching$1$while simultaneously allowing for sublinear-time error-correction. In this paper, we show that multiplicity codes also admit powerful list-decoding and local list-decoding algorithms correcting a large fraction ... more >>> TR12-045 | 22nd April 2012 Eli Ben-Sasson, Alessandro Chiesa, Daniel Genkin, Eran Tromer #### On the Concrete-Efficiency Threshold of Probabilistically-Checkable Proofs Revisions: 3 Probabilistically-Checkable Proofs (PCPs) form the algorithmic core that enables succinct verification of long proofs/computations in many cryptographic constructions, such as succinct arguments and proof-carrying data. Despite the wonderful asymptotic savings they bring, PCPs are also the infamous computational bottleneck preventing these cryptographic constructions from being used in practice. This reflects ... more >>> TR12-046 | 24th April 2012 Madhu Sudan, Noga Ron-Zewi #### A new upper bound on the query complexity for testing generalized Reed-Muller codes Revisions: 1 Over a finite field$\F_q$the$(n,d,q)$-Reed-Muller code is the code given by evaluations of$n$-variate polynomials of total degree at most$d$on all points (of$\F_q^n$). The task of testing if a function$f:\F_q^n \to \F_q$is close to a codeword of an$(n,d,q)$-Reed-Muller code has been of ... more >>> TR12-047 | 24th April 2012 Emanuele Viola #### Extractors for Turing-machine sources We obtain the first deterministic randomness extractors for$n$-bit sources with min-entropy$\ge n^{1-\alpha}$generated (or sampled) by single-tape Turing machines running in time$n^{2-16 \alpha}$, for all sufficiently small$\alpha > 0$. We also show that such machines cannot sample a uniform$n$-bit input to the Inner Product function ... more >>> TR12-048 | 25th April 2012 Alan Guo, Madhu Sudan #### Some closure features of locally testable affine-invariant properties We prove that the class of locally testable affine-invariant properties is closed under sums, intersections and "lifts". The sum and intersection are two natural operations on linear spaces of functions, where the sum of two properties is simply their sum as a vector space. The "lift" is a less natural ... more >>> TR12-049 | 27th April 2012 Eli Ben-Sasson, Noga Ron-Zewi, Madhu Sudan #### Sparse affine-invariant linear codes are locally testable We show that sparse affine-invariant linear properties over arbitrary finite fields are locally testable with a constant number of queries. Given a finite field${\mathbb{F}}_q$and an extension field${\mathbb{F}}_{q^n}$, a property is a set of functions mapping${\mathbb{F}}_{q^n}$to${\mathbb{F}}_q$. The property is said to be affine-invariant if it ... more >>> TR12-050 | 25th April 2012 Avraham Ben-Aroya, Gil Cohen #### Gradual Small-Bias Sample Spaces Revisions: 3 A$(k,\epsilon)$-biased sample space is a distribution over$\{0,1\}^n$that$\epsilon$-fools every nonempty linear test of size at most$k$. Since they were introduced by Naor and Naor [SIAM J. Computing, 1993], these sample spaces have become a central notion in theoretical computer science with a variety of applications. When ... more >>> TR12-051 | 25th April 2012 Dmitry Gavinsky, Shachar Lovett, Michael Saks, Srikanth Srinivasan #### A Tail Bound for Read-k Families of Functions We prove a Chernoff-like large deviation bound on the sum of non-independent random variables that have the following dependence structure. The variables$Y_1,\ldots,Y_r$are arbitrary Boolean functions of independent random variables$X_1,\ldots,X_m$, modulo a restriction that every$X_i$influences at most$k$of the variables$Y_1,\ldots,Y_r$. more >>> TR12-052 | 27th April 2012 Mohammad Mahmoody, David Xiao #### Languages with Efficient Zero-Knowledge PCPs are in SZK A Zero-Knowledge PCP (ZK-PCP) is a randomized PCP such that the view of any (perhaps cheating) efficient verifier can be efficiently simulated up to small statistical distance. Kilian, Petrank, and Tardos (STOC '97) constructed ZK-PCPs for all languages in$NEXP$. Ishai, Mahmoody, and Sahai (TCC '12), motivated by cryptographic applications, ... more >>> TR12-053 | 30th April 2012 Ankur Moitra #### A Singly-Exponential Time Algorithm for Computing Nonnegative Rank Here, we give an algorithm for deciding if the nonnegative rank of a matrix$M$of dimension$m \times n$is at most$r$which runs in time$(nm)^{O(r^2)}$. This is the first exact algorithm that runs in time singly-exponential in$r$. This algorithm (and earlier algorithms) are built on ... more >>> TR12-054 | 2nd May 2012 Eric Allender, Harry Buhrman, Luke Friedman, Bruno Loff #### Reductions to the set of random strings:the resource-bounded case Revisions: 1 This paper is motivated by a conjecture that BPP can be characterized in terms of polynomial-time nonadaptive reductions to the set of Kolmogorov-random strings. In this paper we show that an approach laid out by [Allender et al] to settle this conjecture cannot succeed without significant alteration, but that it ... more >>> TR12-055 | 4th May 2012 Reut Levi, Dana Ron, Ronitt Rubinfeld #### Testing Similar Means We consider the problem of testing a basic property of collections of distributions: having similar means. Namely, the algorithm should accept collections of distributions in which all distributions have means that do not differ by more than some given parameter, and should reject collections that are relatively far from having ... more >>> TR12-056 | 1st May 2012 Rocco Servedio, Li-Yang Tan, Justin Thaler #### Attribute-Efficient Learning and Weight-Degree Tradeoffs for Polynomial Threshold Functions Revisions: 1 We study the challenging problem of learning decision lists attribute-efficiently, giving both positive and negative results. Our main positive result is a new tradeoff between the running time and mistake bound for learning length-$k$decision lists over$n$Boolean variables. When the allowed running time is relatively high, our new ... more >>> TR12-057 | 7th May 2012 Russell Impagliazzo, Raghu Meka, David Zuckerman #### Pseudorandomness from Shrinkage Revisions: 2 One powerful theme in complexity theory and pseudorandomness in the past few decades has been the use of lower bounds to give pseudorandom generators (PRGs). However, the general results using this hardness vs. randomness paradigm suffer a quantitative loss in parameters, and hence do not give nontrivial implications for models ... more >>> TR12-058 | 5th May 2012 Benny Applebaum, Yuval Ishai, Eyal Kushilevitz #### How to Garble Arithmetic Circuits Revisions: 1 Yao's garbled circuit construction transforms a boolean circuit$C:\{0,1\}^n\to\{0,1\}^m$into a garbled circuit''$\hat{C}$along with$n$pairs of$k$-bit keys, one for each input bit, such that$\hat{C}$together with the$n$keys corresponding to an input$x$reveal$C(x)$and no additional information about$x$. The garbled circuit ... more >>> TR12-059 | 14th May 2012 Rahul Santhanam, Ryan Williams #### Uniform Circuits, Lower Bounds, and QBF Algorithms We explore the relationships between circuit complexity, the complexity of generating circuits, and circuit-analysis algorithms. Our results can be roughly divided into three parts: 1. Lower Bounds Against Medium-Uniform Circuits. Informally, a circuit class is medium uniform'' if it can be generated by an algorithmic process that is somewhat complex ... more >>> TR12-060 | 16th May 2012 Parikshit Gopalan, Raghu Meka, Omer Reingold #### DNF Sparsification and a Faster Deterministic Counting Revisions: 2 Given a DNF formula$f$on$n$variables, the two natural size measures are the number of terms or size$s(f)$, and the maximum width of a term$w(f)$. It is folklore that short DNF formulas can be made narrow. We prove a converse, showing that narrow formulas can be ... more >>> TR12-061 | 16th May 2012 Pavel Hrubes, Amir Yehudayoff #### Formulas are exponentially stronger than monotone circuits in non-commutative setting We give an example of a non-commutative monotone polynomial f which can be computed by a polynomial-size non-commutative formula, but every monotone non-commutative circuit computing f must have an exponential size. In the non-commutative setting this gives, a fortiori, an exponential separation between monotone and general formulas, monotone and general ... more >>> TR12-062 | 17th May 2012 Ilan Komargodski, Ran Raz #### Average-Case Lower Bounds for Formula Size Revisions: 2 We give an explicit function$h:\{0,1\}^n\to\{0,1\}$such that any deMorgan formula of size$O(n^{2.499})$agrees with$h$on at most$\frac{1}{2} + \epsilon$fraction of the inputs, where$\epsilon$is exponentially small (i.e.$\epsilon = 2^{-n^{\Omega(1)}}$). Previous lower bounds for formula size were obtained for exact computation. The same ... more >>> TR12-063 | 17th May 2012 Raghav Kulkarni, Miklos Santha #### Query complexity of matroids Let$\mathcal{M}$be a bridgeless matroid on ground set$\{1,\ldots, n\}$and$f_{\mathcal{M}}: \{0,1\}^n \to \{0, 1\}$be the indicator function of its independent sets. A folklore fact is that$f_\mathcal{M}$is evasive," i.e.,$D(f_\mathcal{M}) = n$where$D(f)$denotes the deterministic decision tree complexity of$f.$Here we prove ... more >>> TR12-064 | 10th May 2012 Vitaly Feldman, Elena Grigorescu, Lev Reyzin, Santosh Vempala, Ying Xiao #### Statistical Algorithms and a Lower Bound for Planted Clique Revisions: 2 We develop a framework for proving lower bounds on computational problems over distributions, including optimization and unsupervised learning. Our framework is based on defining a restricted class of algorithms, called statistical algorithms, that instead of accessing samples from the input distribution can only obtain an estimate of the expectation ... more >>> TR12-065 | 16th May 2012 Mohammad Mahmoody, Hemanta Maji, Manoj Prabhakaran #### Limits of Random Oracles in Secure Computation Revisions: 2 The seminal result of Impagliazzo and Rudich (STOC 1989) gave a black-box separation between one-way functions and public-key encryption: informally, a public-key encryption scheme cannot be constructed using one-way functions as the sole source of computational hardness. In addition, this implied a black-box separation between one-way functions and protocols for ... more >>> TR12-066 | 22nd April 2012 Jinyu Huang #### Parallel Complexity for Matroid Intersection and Matroid Parity Problems Revisions: 1 Let two linear matroids have the same rank in matroid intersection. A maximum linear matroid intersection (maximum linear matroid parity set) is called a basic matroid intersection (basic matroid parity set), if its size is the rank of the matroid. We present that enumerating all basic matroid intersections (basic matroid ... more >>> TR12-067 | 6th May 2012 Xiaohui Bei, Ning Chen, Shengyu Zhang #### On the Complexity of Trial and Error Revisions: 1 Motivated by certain applications from physics, biochemistry, economics, and computer science in which the objects under investigation are unknown or not directly accessible because of various limitations, we propose a trial-and-error model to examine search problems with unknown inputs. Given a search problem with a hidden input, we are asked ... more >>> TR12-068 | 25th May 2012 Manuel Arora, Gábor Ivanyos, Marek Karpinski, Nitin Saxena #### Deterministic Polynomial Factoring and Association Schemes The problem of finding a nontrivial factor of a polynomial$f(x)$over a finite field$\mathbb{F}_q$has many known efficient, but randomized, algorithms. The deterministic complexity of this problem is a famous open question even assuming the generalized Riemann hypothesis (GRH). In this work we improve the state of the ... more >>> TR12-069 | 23rd March 2012 Lakhdar Saïs, Mohand-Saïd Hacid, francois hantry #### On the complexity of computing minimal unsatisfiable LTL formulas We show that (1) the Minimal False QCNF search problem (MF-search) and the Minimal Unsatisfiable LTL formula search problem (MU-search) are FPSPACE complete because of the very expressive power of QBF/LTL, (2) we extend the PSPACE-hardness of the MF decision problem to the MU decision problem. As a consequence, we ... more >>> TR12-070 | 26th May 2012 Thomas Watson #### The Complexity of Estimating Min-Entropy Revisions: 1 Goldreich, Sahai, and Vadhan (CRYPTO 1999) proved that the promise problem for estimating the Shannon entropy of a distribution sampled by a given circuit is NISZK-complete. We consider the analogous problem for estimating the min-entropy and prove that it is SBP-complete, even when restricted to 3-local samplers. For logarithmic-space samplers, ... more >>> TR12-071 | 29th May 2012 Kazuhisa Seto, Suguru Tamaki #### A Satisfiability Algorithm and Average-Case Hardness for Formulas over the Full Binary Basis We present a moderately exponential time algorithm for the satisfiability of Boolean formulas over the full binary basis. For formulas of size at most$cn$, our algorithm runs in time$2^{(1-\mu_c)n}$for some constant$\mu_c>0$. As a byproduct of the running time analysis of our algorithm, we get strong ... more >>> TR12-072 | 5th June 2012 Anindya De, Ilias Diakonikolas, Vitaly Feldman, Rocco Servedio #### Nearly optimal solutions for the Chow Parameters Problem and low-weight approximation of halfspaces The \emph{Chow parameters} of a Boolean function$f: \{-1,1\}^n \to \{-1,1\}$are its$n+1$degree-0 and degree-1 Fourier coefficients. It has been known since 1961 \cite{Chow:61, Tannenbaum:61} that the (exact values of the) Chow parameters of any linear threshold function$f$uniquely specify$f$within the space of all Boolean ... more >>> TR12-073 | 11th June 2012 Venkatesan Guruswami, Carol Wang #### Linear-algebraic list decoding for variants of Reed-Solomon codes Folded Reed-Solomon codes are an explicit family of codes that achieve the optimal trade-off between rate and list error-correction capability. Specifically, for any$\epsilon > 0$, Guruswami and Rudra presented an$n^{O(1/\epsilon)}$time algorithm to list decode appropriate folded RS codes of rate$R$from a fraction$1-R-\epsilon$of ... more >>> TR12-074 | 12th June 2012 Venkatesan Guruswami, Yuan Zhou #### Approximating Bounded Occurrence Ordering CSPs A theorem of Håstad shows that for every constraint satisfaction problem (CSP) over a fixed size domain, instances where each variable appears in at most$O(1)$constraints admit a non-trivial approximation algorithm, in the sense that one can beat (by an additive constant) the approximation ratio achieved by the naive ... more >>> TR12-075 | 12th June 2012 Pranjal Awasthi, Madhav Jha, Marco Molinaro, Sofya Raskhodnikova #### Limitations of Local Filters of Lipschitz and Monotone Functions We study local filters for two properties of functions$f:\B^d\to \mathbb{R}$: the Lipschitz property and monotonicity. A local filter with additive error$a$is a randomized algorithm that is given black-box access to a function$f$and a query point$x$in the domain of$f$. Its output is a ... more >>> TR12-076 | 12th June 2012 Pranjal Awasthi, Madhav Jha, Marco Molinaro, Sofya Raskhodnikova #### Testing Lipschitz Functions on Hypergrid Domains A function$f(x_1, ... , x_d)$, where each input is an integer from 1 to$n$and output is a real number, is Lipschitz if changing one of the inputs by 1 changes the output by at most 1. In other words, Lipschitz functions are not very sensitive to small ... more >>> TR12-077 | 10th June 2012 Chiranjit Chakraborty, Rahul Santhanam #### Instance Compression for the Polynomial Hierarchy and Beyond Comments: 2 We define instance compressibility for parametric problems in PH and PSPACE. We observe that the problem \Sigma_{i}CircuitSAT of deciding satisfiability of a quantified Boolean circuit with i-1 alternations of quantifiers starting with an existential uantifier is complete for parametric problems in \Sigma_{i}^{p} with respect to W-reductions, and that analogously ... more >>> TR12-078 | 14th June 2012 Vikraman Arvind, Sebastian Kuhnert, Johannes Köbler, Yadu Vasudev #### Approximate Graph Isomorphism We study optimization versions of Graph Isomorphism. Given two graphs$G_1,G_2$, we are interested in finding a bijection$\pi$from$V(G_1)$to$V(G_2)$that maximizes the number of matches (edges mapped to edges or non-edges mapped to non-edges). We give an$n^{O(\log n)}$time approximation scheme that for any constant ... more >>> TR12-079 | 14th June 2012 Olaf Beyersdorff, Samir Datta, Andreas Krebs, Meena Mahajan, Gido Scharfenberger-Fabian, Karteek Sreenivasaiah, Michael Thomas, Heribert Vollmer #### Verifying Proofs in Constant Depth In this paper we initiate the study of proof systems where verification of proofs proceeds by NC0 circuits. We investigate the question which languages admit proof systems in this very restricted model. Formulated alternatively, we ask which languages can be enumerated by NC0 functions. Our results show that the answer ... more >>> TR12-080 | 18th June 2012 Baris Aydinlioglu, Dieter van Melkebeek #### Nondeterministic Circuit Lower Bounds from Mildly Derandomizing Arthur-Merlin Games In several settings derandomization is known to follow from circuit lower bounds that themselves are equivalent to the existence of pseudorandom generators. This leaves open the question whether derandomization implies the circuit lower bounds that are known to imply it, i.e., whether the ability to derandomize in *any* way implies ... more >>> TR12-081 | 26th June 2012 Neeraj Kayal #### An exponential lower bound for the sum of powers of bounded degree polynomials Revisions: 1 In this work we consider representations of multivariate polynomials in$F[x]$of the form$ f(x) = Q_1(x)^{e_1} + Q_2(x)^{e_2} + ... + Q_s(x)^{e_s},$where the$e_i$'s are positive integers and the$Q_i$'s are arbitary multivariate polynomials of bounded degree. We give an explicit$n$-variate polynomial$f$of degree$n$... more >>> TR12-082 | 28th June 2012 Mahdi Cheraghchi, Venkatesan Guruswami, Ameya Velingker #### Restricted Isometry of Fourier Matrices and List Decodability of Random Linear Codes We prove that a random linear code over$\mathbb{F}_q$, with probability arbitrarily close to$1$, is list decodable at radius$1-1/q-\epsilon$with list size$L=O(1/\epsilon^2)$and rate$R=\Omega_q(\epsilon^2/(\log^3(1/\epsilon)))$. Up to the polylogarithmic factor in$1/\epsilon$and constant factors depending on$q$, this matches the lower bound$L=\Omega_q(1/\epsilon^2)$for the list ... more >>> TR12-083 | 29th June 2012 Thomas Steinke #### Pseudorandomness for Permutation Branching Programs Without the Group Theory We exhibit an explicit pseudorandom generator that stretches an$O \left( \left( w^4 \log w + \log (1/\varepsilon) \right) \cdot \log n \right)$-bit random seed to$n$pseudorandom bits that cannot be distinguished from truly random bits by a permutation branching program of width$w$with probability more than$\varepsilon$. ... more >>> TR12-084 | 3rd July 2012 Rahul Santhanam #### Ironic Complicity: Satisfiability Algorithms and Circuit Lower Bounds I discuss recent progress in developing and exploiting connections between SAT algorithms and circuit lower bounds. The centrepiece of the article is Williams' proof that$NEXP \not \subseteq ACC^0$, which proceeds via a new algorithm for$ACC^0$-SAT beating brute-force search. His result exploits a formal connection from non-trivial SAT algorithms ... more >>> TR12-085 | 5th July 2012 Tsuyoshi Ito, Thomas Vidick #### A multi-prover interactive proof for NEXP sound against entangled provers We prove a strong limitation on the ability of entangled provers to collude in a multiplayer game. Our main result is the first nontrivial lower bound on the class MIP* of languages having multi-prover interactive proofs with entangled provers; namely MIP* contains NEXP, the class of languages decidable in non-deterministic ... more >>> TR12-086 | 4th July 2012 Shlomi Dolev, Nova Fandina, Dan Gutfreund #### Succinct Permanent is NEXP-hard with Many Hard Instances Finding a problem that is both hard to solve and hard to solve on many instances is a long standing issue in theoretical computer science. In this work, we prove that the Succinct Permanent$\bmod \; p$is$NEXP$time hard in the worst case (via randomized polynomial time ... more >>> TR12-087 | 4th July 2012 Peyman Afshani, Manindra Agrawal, Doerr Benjamin, Winzen Carola, Kasper Green Larsen, Kurt Mehlhorn #### The Deterministic and Randomized Query Complexity of a Simple Guessing Game Revisions: 1 We study the$\leadingones$game, a Mastermind-type guessing game first regarded as a test case in the complexity theory of randomized search heuristics. The first player, Carole, secretly chooses a string$z \in \{0,1\}^n$and a permutation$\pi$of$[n]$. The goal of the second player, Paul, is to ... more >>> TR12-088 | 7th July 2012 Irit Dinur, Gillat Kol #### Covering CSPs We study the covering complexity of constraint satisfaction problems (CSPs). The covering number of a CSP instance C, denoted$\nu(C)$, is the smallest number of assignments to the variables, such that each constraint is satisfied by at least one of the assignments. This covering notion describes situations in which we ... more >>> TR12-089 | 7th July 2012 Meena Boppana #### Lattice Variant of the Sensitivity Conjecture The Sensitivity Conjecture, posed in 1994, states that the fundamental measures known as the sensitivity and block sensitivity of a Boolean function$f$,$s(f)$and$bs(f)$respectively, are polynomially related. It is known that$bs(f)$is polynomially related to important measures in computer science including the decision-tree depth, polynomial degree, ... more >>> TR12-090 | 2nd July 2012 Michael Blondin, Andreas Krebs, Pierre McKenzie #### The Complexity of Intersecting Finite Automata Having Few Final States The problem of determining whether several finite automata accept a word in common is closely related to the well-studied membership problem in transformation monoids. We raise the issue of limiting the number of final states in the automata intersection problem. For automata with two final states, we show the problem ... more >>> TR12-091 | 16th July 2012 Abuzer Yakaryilmaz #### One-counter verifiers for decidable languages Condon and Lipton (FOCS 1989) showed that the class of languages having a space-bounded interactive proof system (IPS) is a proper subset of decidable languages, where the verifier is a probabilistic Turing machine. In this paper, we show that if we use architecturally restricted verifiers instead of restricting the working ... more >>> TR12-092 | 6th July 2012 Pavol Duris #### A Note On the Hierarchy of One-way Data-Independent Multi-Head Finite Automata. In this paper we deal with one-way multi-head data-independent finite automata. A$k$-head finite automaton$A$is data-independent, if the position of every head$i$after step$t$in the computation on an input$w$is a function that depends only on the length of the input$w$, on$i$... more >>> TR12-093 | 1st July 2012 Charanjit Jutla, Vijay Kumar, Atri Rudra #### On the Circuit Complexity of Composite Galois Field Transformations We study the circuit complexity of linear transformations between Galois fields GF(2^{mn}) and their isomorphic composite fields GF((2^{m})^n). For such a transformation, we show a lower bound of \Omega(mn) on the number of gates required in any circuit consisting of constant-fan-in XOR gates, except for a class of transformations between ... more >>> TR12-094 | 19th July 2012 Sanjeev Arora, Arnab Bhattacharyya, Rajsekar Manokaran, Sushant Sachdeva #### Testing Permanent Oracles -- Revisited Suppose we are given an oracle that claims to approximate the permanent for most matrices$X$, where$X$is chosen from the Gaussian ensemble (the matrix entries are i.i.d. univariate complex Gaussians). Can we test that the oracle satisfies this claim? This paper gives a polynomial-time algorithm for the task. ... more >>> TR12-095 | 23rd July 2012 Avraham Ben-Aroya, Igor Shinkar #### A Note on Subspace Evasive Sets A subspace-evasive set over a field${\mathbb F}$is a subset of${\mathbb F}^n$that has small intersection with any low-dimensional affine subspace of${\mathbb F}^n$. Interest in subspace evasive sets began in the work of Pudlák and Rödl (Quaderni di Matematica 2004). More recently, Guruswami (CCC 2011) showed that ... more >>> TR12-096 | 17th July 2012 Albert Atserias, Sergi Oliva #### Bounded-width QBF is PSPACE-complete Revisions: 3 Tree-width is a well-studied parameter of structures that measures their similarity to a tree. Many important NP-complete problems, such as Boolean satisfiability (SAT), are tractable on bounded tree-width instances. In this paper we focus on the canonical PSPACE-complete problem QBF, the fully-quantified version of SAT. It was shown by Pan ... more >>> TR12-097 | 26th July 2012 Andrej Bogdanov, Siyao Guo #### Sparse extractor families for all the entropy We consider the problem of extracting entropy by sparse transformations, namely functions with a small number of overall input-output dependencies. In contrast to previous works, we seek extractors for essentially all the entropy without any assumption on the underlying distribution beyond a min-entropy requirement. We give two simple constructions of ... more >>> TR12-098 | 3rd August 2012 Ankit Gupta, Pritish Kamath, Neeraj Kayal, Ramprasad Saptharishi #### An exponential lower bound for homogeneous depth four arithmetic circuits with bounded bottom fanin Revisions: 3 Agrawal and Vinay (FOCS 2008) have recently shown that an exponential lower bound for depth four homogeneous circuits with bottom layer of$\times$gates having sublinear fanin translates to an exponential lower bound for a general arithmetic circuit computing the permanent. Motivated by this, we examine the complexity of computing ... more >>> TR12-099 | 5th August 2012 Nikos Leonardos #### An improved lower bound for the randomized decision tree complexity of recursive majority Revisions: 1 We prove that the randomized decision tree complexity of the recursive majority-of-three is$\Omega(2.6^d)$, where$d$is the depth of the recursion. The proof is by a bottom up induction, which is same in spirit as the one in the proof of Saks and Wigderson in their FOCS 1986 paper ... more >>> TR12-100 | 23rd July 2012 Tomas Jirotka #### NP Search Problems The thesis summarizes known results in the field of NP search problems. We discuss the complexity of integer factoring in detail, and we propose new results which place the problem in known classes and aim to separate it from PLS in some sense. Furthermore, we define several new search problems. more >>> TR12-101 | 10th August 2012 Oded Goldreich, Shafi Goldwasser, Dana Ron #### On the possibilities and limitations of pseudodeterministic algorithms We study the possibilities and limitations of pseudodeterministic algorithms, a notion put forward by Gat and Goldwasser (2011). These are probabilistic algorithms that solve search problems such that on each input, with high probability, they output the same solution, which may be thought of as a canonical solution. We consider ... more >>> TR12-102 | 16th August 2012 Swastik Kopparty, Srikanth Srinivasan #### Certifying Polynomials for$\mathrm{AC}^0[\oplus]$circuits, with applications In this paper, we introduce and develop the method of certifying polynomials for proving$\mathrm{AC}^0[\oplus]$circuit lower bounds. We use this method to show that Approximate Majority cannot be computed by$\mathrm{AC}^0[\oplus]$circuits of size$n^{1+o(1)}$. This implies a separation between the power of$\mathrm{AC}^0[\oplus]$circuits of near-linear size and ... more >>> TR12-103 | 16th August 2012 Arnab Bhattacharyya, Yuichi Yoshida #### Testing Assignments of Boolean CSPs Given an instance$\mathcal{I}$of a CSP, a tester for$\mathcal{I}$distinguishes assignments satisfying$\mathcal{I}$from those which are far from any assignment satisfying$\mathcal{I}$. The efficiency of a tester is measured by its query complexity, the number of variable assignments queried by the algorithm. In this paper, we characterize ... more >>> TR12-104 | 8th August 2012 Matthew Franklin, Ran Gelles, Rafail Ostrovsky, Leonard Schulman #### Optimal Coding for Streaming Authentication and Interactive Communication Revisions: 1 Error correction and message authentication are well studied in the literature, and various efficient solutions have been suggested and analyzed. This is however not the case for data streams in which the message is very long, possibly infinite, and not known in advance to the sender. Trivial solutions for error-correcting ... more >>> TR12-105 | 17th August 2012 Madhur Tulsiani, Pratik Worah ####$LS_+$Lower Bounds from Pairwise Independence We consider the complexity of LS$_+$refutations of unsatisfiable instances of Constraint Satisfaction Problems (CSPs) when the underlying predicate supports a pairwise independent distribution on its satisfying assignments. This is the most general condition on the predicates under which the corresponding MAX-CSP problem is known to be approximation resistant. We ... more >>> TR12-106 | 27th August 2012 Alan Guo, Madhu Sudan #### New affine-invariant codes from lifting Comments: 1 In this work we explore error-correcting codes derived from the lifting'' of affine-invariant'' codes. Affine-invariant codes are simply linear codes whose coordinates are a vector space over a field and which are invariant under affine-transformations of the coordinate space. Lifting takes codes defined over a vector space of small dimension ... more >>> TR12-107 | 30th August 2012 Brendan Juba, Ryan Williams #### Massive Online Teaching to Bounded Learners We consider a model of teaching in which the learners are consistent and have bounded state, but are otherwise arbitrary. The teacher is non-interactive and massively open'': the teacher broadcasts a sequence of examples of an arbitrary target concept, intended for every possible on-line learning algorithm to learn from. We ... more >>> TR12-108 | 4th September 2012 Arkadev Chattopadhyay, Rahul Santhanam #### Lower Bounds on Interactive Compressibility by Constant-Depth Circuits We formulate a new connection between instance compressibility \cite{Harnik-Naor10}), where the compressor uses circuits from a class$\C$, and correlation with circuits in$\C$. We use this connection to prove the first lower bounds on general probabilistic multi-round instance compression. We show that there is no probabilistic multi-round ... more >>> TR12-109 | 31st August 2012 Subhash Khot, Muli Safra, Madhur Tulsiani #### Towards An Optimal Query Efficient PCP? We construct a PCP based on the hyper-graph linearity test with 3 free queries. It has near-perfect completeness and soundness strictly less than 1/8. Such a PCP was known before only assuming the Unique Games Conjecture, albeit with soundness arbitrarily close to 1/16. At a technical level, our ... more >>> TR12-110 | 4th September 2012 Siu On Chan #### Approximation Resistance from Pairwise Independent Subgroups We show optimal (up to constant factor) NP-hardness for Max-k-CSP over any domain, whenever k is larger than the domain size. This follows from our main result concerning predicates over abelian groups. We show that a predicate is approximation resistant if it contains a subgroup that is ... more >>> TR12-111 | 5th September 2012 Venkatesan Guruswami, Ali Kemal Sinop #### Faster SDP hierarchy solvers for local rounding algorithms Convex relaxations based on different hierarchies of linear/semi-definite programs have been used recently to devise approximation algorithms for various optimization problems. The approximation guarantee of these algorithms improves with the number of {\em rounds}$r$in the hierarchy, though the complexity of solving (or even writing down the solution for) ... more >>> TR12-112 | 7th September 2012 Andrew Drucker #### New Limits to Classical and Quantum Instance Compression Revisions: 3 Given an instance of a hard decision problem, a limited goal is to$compress$that instance into a smaller, equivalent instance of a second problem. As one example, consider the problem where, given Boolean formulas$\psi^1, \ldots, \psi^t$, we must determine if at least one$\psi^j$is satisfiable. An$OR-compression ... more >>>

TR12-113 | 7th September 2012
Manindra Agrawal, Chandan Saha, Nitin Saxena

#### Quasi-polynomial Hitting-set for Set-depth-$\Delta$ Formulas

We call a depth-$4$ formula $C$ $\textit{ set-depth-4}$ if there exists a (unknown) partition $X_1\sqcup\cdots\sqcup X_d$ of the variable indices $[n]$ that the top product layer respects, i.e. $C(\mathbf{x})=\sum_{i=1}^k {\prod_{j=1}^{d} {f_{i,j}(\mathbf{x}_{X_j})}}$ $,$ where $f_{i,j}$ is a $\textit{sparse}$ polynomial in $\mathbb{F}[\mathbf{x}_{X_j}]$. Extending this definition to any depth - we call ... more >>>

TR12-114 | 15th July 2012
Mikhail Anokhin

#### Constructing a Pseudo-Free Family of Finite Computational Groups under the General Integer Factoring Intractability Assumption

Revisions: 4

We construct a provably pseudo-free family of finite computational groups under the general integer factoring intractability assumption. Moreover, this family has exponential size. But each element of a group in our pseudo-free family is represented by many bit strings.

more >>>

TR12-115 | 11th September 2012
Michael Forbes, Amir Shpilka

#### Quasipolynomial-time Identity Testing of Non-Commutative and Read-Once Oblivious Algebraic Branching Programs

Revisions: 1

We study the problem of obtaining efficient, deterministic, black-box polynomial identity testing (PIT) algorithms for read-once oblivious algebraic branching programs (ABPs). This class has an efficient, deterministic, white-box polynomial identity testing algorithm (due to Raz and Shpilka), but prior to this work had no known such black-box algorithm. Here we ... more >>>

TR12-116 | 13th September 2012
Luca Trevisan

#### A Derandomized Switching Lemma and an Improved Derandomization of AC0

Revisions: 1

We describe a new pseudorandom generator for AC0. Our generator $\epsilon$-fools circuits of depth $d$ and size $M$ and uses a seed of length $\tilde O( \log^{d+4} M/\epsilon)$. The previous best construction for $d \geq 3$ was due to Nisan, and had seed length $O(\log^{2d+6} M/\epsilon)$.
A seed length of ... more >>>

TR12-117 | 17th September 2012
Loïck Magnin, Jérémie Roland

#### Explicit relation between all lower bound techniques for quantum query complexity

The polynomial method and the adversary method are the two main techniques to prove lower bounds on quantum query complexity, and they have so far been considered as unrelated approaches. Here, we show an explicit reduction from the polynomial method to the multiplicative adversary method. The proof goes by extending ... more >>>

TR12-118 | 18th September 2012
Avi Wigderson, Amir Yehudayoff

#### Population Recovery and Partial Identification

We study several problems in which an {\em unknown} distribution over an {\em unknown} population of vectors needs to be recovered from partial or noisy samples, each of which nearly completely erases or obliterates the original vector. For example, consider a distribution $p$ over a population $V \subseteq \{0,1\}^n$. A ... more >>>

TR12-119 | 24th September 2012
Ilario Bonacina, Nicola Galesi

#### Pseudo-partitions, Transversality and Locality: A Combinatorial Characterization for the Space Measure in Algebraic Proof Systems

We devise a new combinatorial characterization for proving space lower bounds in algebraic systems like Polynomial Calculus (Pc) and Polynomial Calculus with Resolution (Pcr). Our method can be thought as a Spoiler-Duplicator game, which is capturing boolean reasoning on polynomials instead that clauses as in the case of Resolution. Hence, ... more >>>

TR12-120 | 24th September 2012
Boaz Barak

#### Proof vs. Truth in Computational Complexity

Revisions: 1

In this survey, I discuss the general question of what evidence can we use to predict the answer for open questions in computational complexity, as well as the concrete evidence currently known for two conjectures: Khot's Unique Games Conjecture and Feige's Random 3SAT Hypothesis.

more >>>

TR12-121 | 25th September 2012
Pavel Hrubes

#### A note on the real $\tau$-conjecture and the distribution of roots

Revisions: 2

Koiran's real $\tau$-conjecture asserts that if a non-zero real polynomial can be written as $f=\sum_{i=1}^{p}\prod_{j=1}^{q}f_{ij},$
where each $f_{ij}$ contains at most $k$ monomials, then the number of distinct real roots of $f$ is polynomial in $pqk$. We show that the conjecture implies quite a strong property of the ... more >>>

TR12-122 | 17th September 2012
Giorgio Ausiello, Francesco Cristiano, Luigi Laura

#### Syntactic Isomorphism of CNF Boolean Formulas is Graph Isomorphism Complete

We investigate the complexity of the syntactic isomorphism problem of CNF Boolean Formulas (CSFI): given two CNF Boolean formulas $\varphi(a_{1},\ldots,a_{n})$ and $\varphi(b_{1},\ldots,b_{n})$ decide whether there exists a permutation of clauses, a permutation of literals and a bijection between their variables such that $\varphi(a_{1},\ldots,a_{n})$ and $\varphi(b_{1},\ldots,b_{n})$ become syntactically identical. We first ... more >>>

TR12-123 | 28th September 2012
Parikshit Gopalan, Raghu Meka, Omer Reingold, Luca Trevisan, Salil Vadhan

#### Better pseudorandom generators from milder pseudorandom restrictions

We present an iterative approach to constructing pseudorandom generators, based on the repeated application of mild pseudorandom restrictions. We use this template to construct pseudorandom generators for combinatorial rectangles and read-once CNFs and a hitting set generator for width-3 branching programs, all of which achieve near optimal seed-length even in ... more >>>

TR12-124 | 29th September 2012
Massimo Lauria

#### A rank lower bound for cutting planes proofs of Ramsey Theorem

Ramsey Theorem is a cornerstone of combinatorics and logic. In its
simplest formulation it says that there is a function $r$ such that
any simple graph with $r(k,s)$ vertices contains either a clique of
size $k$ or an independent set of size $s$. We study the complexity
of proving upper ... more >>>

TR12-125 | 2nd October 2012
Zahra Jafargholi, Hamidreza Jahanjou, Eric Miles, Jaideep Ramachandran, Emanuele Viola

#### From RAM to SAT

Revisions: 1

Common presentations of the NP-completeness of SAT suffer
from two drawbacks which hinder the scope of this
flagship result. First, they do not apply to machines
equipped with random-access memory, also known as
direct-access memory, even though this feature is
critical in basic algorithms. Second, they incur a
quadratic blow-up ... more >>>

TR12-126 | 23rd September 2012
Shiva Kintali, Sinziana Munteanu

#### Computing Bounded Path Decompositions in Logspace

We present a logspace algorithm to compute path decompositions of bounded pathwidth graphs, thus settling its complexity. Prior to our work, the best known upper bound to compute such decompositions was linear time. We also show that deciding if the pathwidth of a graph is at most a given constant ... more >>>

TR12-127 | 3rd October 2012
Eshan Chattopadhyay, Adam Klivans, Pravesh Kothari

#### An Explicit VC-Theorem for Low-Degree Polynomials

Let $X \subseteq \mathbb{R}^{n}$ and let ${\mathcal C}$ be a class of functions mapping $\mathbb{R}^{n} \rightarrow \{-1,1\}.$ The famous VC-Theorem states that a random subset $S$ of $X$ of size $O(\frac{d}{\epsilon^{2}} \log \frac{d}{\epsilon})$, where $d$ is the VC-Dimension of ${\mathcal C}$, is (with constant probability) an $\epsilon$-approximation for ${\mathcal C}$ ... more >>>

TR12-128 | 21st September 2012
Nathanaël François, Frederic Magniez

#### Streaming Complexity of Checking Priority Queues

Revisions: 1

This work is in the line of designing efficient checkers for testing the reliability of some massive data structures. Given a sequential access to the insert/extract operations on such a structure, one would like to decide, a posteriori only, if it corresponds to the evolution of a reliable structure. In ... more >>>

TR12-129 | 9th October 2012
Iftach Haitner, Eran Omri, Hila Zarosim

#### On the Power of Random Oracles

Revisions: 3

In the random oracle model, the parties are given oracle access to a random member of
a (typically huge) function family, and are assumed to have unbounded computational power
(though they can only make a bounded number of oracle queries). This model provides powerful
properties that allow proving the security ... more >>>

TR12-130 | 3rd October 2012
Abuzer Yakaryilmaz

#### Public-qubits versus private-coins

We introduce a new public quantum interactive proof system, namely qAM, by augmenting the verifier with a fixed-size quantum register in Arthur-Merlin game. We focus on space-bounded verifiers, and compare our new public system with private-coin interactive proof (IP) system in the same space bounds. We show that qAM systems ... more >>>

TR12-131 | 18th October 2012
Mark Braverman, Ankur Moitra

#### An Information Complexity Approach to Extended Formulations

Revisions: 1

We prove an unconditional lower bound that any linear program that achieves an $O(n^{1-\epsilon})$ approximation for clique has size $2^{\Omega(n^\epsilon)}$. There has been considerable recent interest in proving unconditional lower bounds against any linear program. Fiorini et al proved that there is no polynomial sized linear program for traveling salesman. ... more >>>

TR12-132 | 21st October 2012
Yuval Filmus, Massimo Lauria, Jakob Nordström, Noga Ron-Zewi, Neil Thapen

#### Space Complexity in Polynomial Calculus

During the last decade, an active line of research in proof complexity has been to study space complexity and time-space trade-offs for proofs. Besides being a natural complexity measure of intrinsic interest, space is also an important issue in SAT solving, and so research has mostly focused on weak systems ... more >>>

TR12-133 | 21st October 2012
Noga Alon, Gil Cohen

#### On Rigid Matrices and Subspace Polynomials

Revisions: 1

We introduce a class of polynomials, which we call \emph{subspace polynomials} and show that the problem of explicitly constructing a rigid matrix can be reduced to the problem of explicitly constructing a small hitting set for this class. We prove that small-bias sets are hitting sets for the class of ... more >>>

TR12-134 | 22nd October 2012
Alexander Razborov, Emanuele Viola

#### Real Advantage

Revisions: 1

We highlight the challenge of proving correlation bounds
between boolean functions and integer-valued polynomials,
where any non-boolean output counts against correlation.

We prove that integer-valued polynomials of degree $\frac 12 \log_2 \log_2 n$ have zero correlation with parity. Such a
result is false for modular and threshold polynomials.
Its proof ... more >>>

TR12-135 | 26th October 2012
Eli Ben-Sasson, Noga Ron-Zewi, Madhur Tulsiani, Julia Wolf

#### Sampling-based proofs of almost-periodicity results and algorithmic applications

Revisions: 2

We give new combinatorial proofs of known almost-periodicity results for sumsets of sets with small doubling in the spirit of Croot and Sisask [Geom. Funct. Anal. 2010], whose almost-periodicity lemma has had far-reaching implications in additive combinatorics. We provide an alternative (and $L^p$-norm free) point of view, which allows for ... more >>>

TR12-136 | 26th October 2012
Dan Boneh, Mark Zhandry

#### Quantum-Secure Message Authentication Codes

Revisions: 2

We construct the first Message Authentication Codes (MACs) that are existentially unforgeable against a quantum chosen message attack. These chosen message attacks model a quantum adversary’s ability to obtain the MAC on a superposition of messages of its choice. We begin by showing that a quantum secure PRF is sufficient ... more >>>

TR12-137 | 1st November 2012
Johan Hastad

#### On the correlation of parity and small-depth circuits

Revisions: 1

We prove that the correlation of a depth-$d$
unbounded fanin circuit of size $S$ with parity
of $n$ variables is at most $2^{-\Omega(n/(\log S)^{d-1})}$.

more >>>

TR12-138 | 2nd November 2012
Zeev Dvir, Shubhangi Saraf, Avi Wigderson

#### Improved rank bounds for design matrices and a new proof of Kelly's theorem

We study the rank of complex sparse matrices in which the supports of different columns have small intersections. The rank of these matrices, called design matrices, was the focus of a recent work by Barak et. al. (BDWY11) in which they were used to answer questions regarding point configurations. In ... more >>>

TR12-139 | 2nd November 2012
Albert Ai, Zeev Dvir, Shubhangi Saraf, Avi Wigderson

#### Sylvester-Gallai type theorems for approximate collinearity

We study questions in incidence geometry where the precise position of points is blurry' (e.g. due to noise, inaccuracy or error). Thus lines are replaced by narrow tubes, and more generally affine subspaces are replaced by their small neighborhood. We show that the presence of a sufficiently large number of ... more >>>

TR12-140 | 27th October 2012
Mark Zhandry

#### How to Construct Quantum Random Functions

Revisions: 2

In the presence of a quantum adversary, there are two possible definitions of security for a pseudorandom function. The first, which we call standard-security, allows the adversary to be quantum, but requires queries to the function to be classical. The second, quantum-security, allows the adversary to query the function on ... more >>>

TR12-141 | 22nd October 2012
Dmitry Itsykson, Dmitry Sokolov

#### Lower bounds for myopic DPLL algorithms with a cut heuristic

The paper is devoted to lower bounds on the time complexity of DPLL algorithms that solve the satisfiability problem using a splitting strategy. Exponential lower bounds on the running time of DPLL algorithms on unsatisfiable formulas follow from the lower bounds for resolution proofs. Lower bounds on satisfiable instances are ... more >>>

TR12-142 | 3rd November 2012
Markus Bläser

#### Noncommutativity makes determinants hard

We consider the complexity of computing the determinant over arbitrary finite-dimensional algebras. We first consider the case that $A$ is fixed. We obtain the following dichotomy: If $A/rad(A)$ is noncommutative, then computing the determinant over $A$ is hard. Hard'' here means $\#P$-hard over fields of characteristic $0$ and $ModP_p$-hard over ... more >>>

TR12-143 | 5th November 2012
Mark Braverman, Anup Rao, Omri Weinstein, Amir Yehudayoff

#### Direct Products in Communication Complexity

Revisions: 2

We give exponentially small upper bounds on the success probability for computing the direct product of any function over any distribution using a communication protocol. Let suc(?,f,C) denote the maximum success probability of a 2-party communication protocol for computing f(x,y) with C bits of communication, when the inputs (x,y) are ... more >>>

TR12-144 | 6th November 2012
Rocco Servedio, Emanuele Viola

#### On a special case of rigidity

We highlight the special case of Valiant's rigidity
problem in which the low-rank matrices are truth-tables
of sparse polynomials. We show that progress on this
special case entails that Inner Product is not computable
by small $\acz$ circuits with one layer of parity gates
close to the inputs. We then ... more >>>

TR12-145 | 31st October 2012
Cenny Wenner

#### Circumventing d-to-1 for Approximation Resistance of Satisfiable Predicates Strictly Containing Parity of Width at Least Four

Håstad established that any predicate $P \subseteq \{0,1\}^m$ containing parity of width at least three is approximation resistant for almost satisfiable instances. However, in comparison to for example the approximation hardness of Max-3SAT, the result only holds for almost satisfiable instances. This limitation was addressed by O'Donnell, Wu, and Huang ... more >>>

TR12-146 | 7th November 2012
Venkatesan Guruswami, Chaoping Xing

#### List decoding Reed-Solomon, Algebraic-Geometric, and Gabidulin subcodes up to the Singleton bound

We consider Reed-Solomon (RS) codes whose evaluation points belong to a subfield, and give a linear-algebraic list decoding algorithm that can correct a fraction of errors approaching the code distance, while pinning down the candidate messages to a well-structured affine space of dimension a constant factor smaller than the code ... more >>>

TR12-147 | 7th November 2012
Xin Li

#### New Independent Source Extractors with Exponential Improvement

We study the problem of constructing explicit extractors for independent general weak random sources. For weak sources on $n$ bits with min-entropy $k$, perviously the best known extractor needs to use at least $\frac{\log n}{\log k}$ independent sources \cite{Rao06, BarakRSW06}. In this paper we give a new extractor that only ... more >>>

TR12-148 | 7th November 2012
Eli Ben-Sasson, Ariel Gabizon, Yohay Kaplan, Swastik Kopparty, Shubhangi Saraf

#### A new family of locally correctable codes based on degree-lifted algebraic geometry codes

Revisions: 1

We describe new constructions of error correcting codes, obtained by "degree-lifting" a short algebraic geometry (AG) base-code of block-length $q$ to a lifted-code of block-length $q^m$, for arbitrary integer $m$. The construction generalizes the way degree-$d$, univariate polynomials evaluated over the $q$-element field (also known as Reed-Solomon codes) are "lifted" ... more >>>

TR12-149 | 8th November 2012
Alan Guo, Swastik Kopparty, Madhu Sudan

#### New affine-invariant codes from lifting

Comments: 1

In this work we explore error-correcting codes derived from
the lifting'' of affine-invariant'' codes.
Affine-invariant codes are simply linear codes whose coordinates
are a vector space over a field and which are invariant under
affine-transformations of the coordinate space. Lifting takes codes
defined over a vector space of small dimension ... more >>>

TR12-150 | 1st November 2012
Michael Elberfeld, Christoph Stockhusen, Till Tantau

#### On the Space Complexity of Parameterized Problems

Revisions: 1

Parameterized complexity theory measures the complexity of computational problems predominantly in terms of their parameterized time complexity. The purpose of the present paper is to demonstrate that the study of parameterized space complexity can give new insights into the complexity of well-studied parameterized problems like the feedback vertex set problem. ... more >>>

TR12-151 | 6th November 2012
Subhash Khot, Madhur Tulsiani, Pratik Worah

#### The Complexity of Somewhat Approximation Resistant Predicates

Revisions: 1

A boolean predicate $f:\{0,1\}^k\to\{0,1\}$ is said to be {\em somewhat approximation resistant} if for some constant $\tau > \frac{|f^{-1}(1)|}{2^k}$, given a $\tau$-satisfiable instance of the MAX-$k$-CSP$(f)$ problem, it is NP-hard to find an assignment that {\it strictly beats} the naive algorithm that outputs a uniformly random assignment. Let $\tau(f)$ denote ... more >>>

TR12-152 | 7th November 2012
Anindya De, Ilias Diakonikolas, Rocco Servedio

#### Inverse Problems in Approximate Uniform Generation

We initiate the study of \emph{inverse} problems in approximate uniform generation, focusing on uniform generation of satisfying assignments of various types of Boolean functions. In such an inverse problem, the algorithm is given uniform random satisfying assignments of an unknown function $f$ belonging to a class $\C$ of Boolean functions ... more >>>

TR12-153 | 9th November 2012
Joshua Brody, Amit Chakrabarti, Ranganath Kondapally

#### Certifying Equality With Limited Interaction

Revisions: 1

The \textsc{equality} problem is usually one's first encounter with
communication complexity and is one of the most fundamental problems in the
field. Although its deterministic and randomized communication complexity
were settled decades ago, we find several new things to say about the
problem by focusing on two subtle aspects. The ... more >>>

TR12-154 | 31st October 2012
Sourav Chakraborty, Eldar Fischer, Yonatan Goldhirsh, Arie Matsliah

#### On the Power of Conditional Samples in Distribution Testing

Revisions: 1

In this paper we define and examine the power of the conditional-sampling oracle in the context of distribution-property testing. The conditional-sampling oracle for a discrete distribution $\mu$ takes as input a subset $S \subset [n]$ of the domain, and outputs a random sample $i \in S$ drawn according to $\mu$, ... more >>>

TR12-155 | 15th November 2012
Clement Canonne, Dana Ron, Rocco Servedio

#### Testing probability distributions using conditional samples

Revisions: 1

We study a new framework for property testing of probability distributions, by considering distribution testing algorithms that have access to a conditional sampling oracle. \footnote{Independently from our work, Chakraborty et al. [CFGM13] also considered this framework. We discuss their work in Subsection 1.4.} This is an oracle that takes as ... more >>>

TR12-156 | 12th November 2012
Andrej Bogdanov, Chin Ho Lee

#### Limits of provable security for homomorphic encryption

Revisions: 1

We show that public-key bit encryption schemes which support weak homomorphic evaluation of parity or majority cannot be proved message indistinguishable beyond AM intersect coAM via general (adaptive) reductions, and beyond statistical zero-knowledge via reductions of constant query complexity.

Previous works on the limitation of reductions for proving security of ... more >>>

TR12-157 | 12th November 2012
Andrej Bogdanov, Chin Ho Lee

#### On the depth complexity of homomorphic encryption schemes

Revisions: 2

We show that secure homomorphic evaluation of any non-trivial functionality of sufficiently many inputs with respect to any CPA secure encryption scheme cannot be implemented by constant depth, polynomial size circuits, i.e. in the class AC0. In contrast, we observe that certain previously studied encryption schemes (with quasipolynomial security) can ... more >>>

TR12-158 | 14th November 2012
Aditya Bhaskara, Devendra Desai, Srikanth Srinivasan

#### Optimal Hitting Sets for Combinatorial Shapes

We consider the problem of constructing explicit Hitting sets for Combinatorial Shapes, a class of statistical tests first studied by Gopalan, Meka, Reingold, and Zuckerman (STOC 2011). These generalize many well-studied classes of tests, including symmetric functions and combinatorial rectangles. Generalizing results of Linial, Luby, Saks, and Zuckerman (Combinatorica 1997) ... more >>>

TR12-159 | 20th November 2012
Eli Ben-Sasson, Michael Viderman

#### A Combinatorial Characterization of smooth LTCs and Applications

The study of locally testable codes (LTCs) has benefited from a number of nontrivial constructions discovered in recent years. Yet we still lack a good understanding of what makes a linear error correcting code locally testable and as a result we do not know what is the rate-limit of LTCs ... more >>>

TR12-160 | 20th November 2012
Frederic Green, Daniel Kreymer, Emanuele Viola

#### Block-symmetric polynomials correlate with parity better than symmetric

We show that degree-$d$ block-symmetric polynomials in
$n$ variables modulo any odd $p$ correlate with parity
exponentially better than degree-$d$ symmetric
polynomials, if $n \ge c d^2 \log d$ and $d \in [0.995 \cdot p^t - 1,p^t)$ for some $t \ge 1$. For these
infinitely many degrees, our result ... more >>>

TR12-161 | 20th November 2012
Olaf Beyersdorff, Nicola Galesi, Massimo Lauria

#### A Characterization of Tree-Like Resolution Size

We explain an asymmetric Prover-Delayer game which precisely characterizes proof size in tree-like Resolution. This game was previously described in a parameterized complexity context to show lower bounds for parameterized formulas and for the classical pigeonhole principle. The main point of this note is to show that the asymmetric game ... more >>>

TR12-162 | 26th October 2012
Hans-Joachim Boeckenhauer, Juraj Hromkovic, Dennis Komm, Sacha Krug, Jasmin Smula, Andreas Sprock

#### The String Guessing Problem as a Method to Prove Lower Bounds on the Advice Complexity

Revisions: 1

The advice complexity of an online problem describes the additional information both necessary and sufficient for online algorithms to compute solutions of a certain quality. In this model, an oracle inspects the input before it is processed by an online algorithm. Depending on the input string, the oracle prepares an ... more >>>

TR12-163 | 24th November 2012
Avishay Tal

#### Properties and Applications of Boolean Function Composition

For Boolean functions $f:\{0,1\}^n \to \{0,1\}$ and $g:\{0,1\}^m \to \{0,1\}$, the function composition of $f$ and $g$ denoted by $f\circ g : \{0,1\}^{nm} \to \{0,1\}$ is the value of $f$ on $n$ inputs, each of them is the calculation of $g$ on a distinct set of $m$ Boolean variables. Motivated ... more >>>

TR12-164 | 17th November 2012
Rafail Ostrovsky, Ivan Visconti

#### Simultaneous Resettability from Collision Resistance

In FOCS 2001, Barak, Goldreich, Goldwasser and Lindell conjectured that the existence of ZAPs, introduced by Dwork and Naor in FOCS 2000, could lead to the design of a zero-knowledge proof system that is secure against both resetting provers and resetting verifiers. Their conjecture has been proven true by Deng, ... more >>>

TR12-165 | 19th November 2012
Martin Albrecht, Pooya Farshim, Jean-Charles Faugère, Gottfried Herold, Ludovic Perret

#### Polly Cracker, Revisited

We initiate the formal treatment of cryptographic constructions based on the hardness of computing remainders modulo an ideal in multivariate polynomial rings. Of particular interest to us is a class of schemes known as "Polly Cracker." We start by formalising and studying the relation between the ideal remainder problem and ... more >>>

TR12-166 | 25th November 2012
Elad Haramaty, Madhu Sudan

#### Deterministic Compression with Uncertain Priors

We consider the task of compression of information when the source of the information and the destination do not agree on the prior, i.e., the distribution from which the information is being generated. This setting was considered previously by Kalai et al. (ICS 2011) who suggested that this was a ... more >>>

TR12-167 | 16th November 2012
Periklis Papakonstantinou, Charles Rackoff, Yevgeniy Vahlis

#### How powerful are the DDH hard groups?

The question whether Identity-Based Encryption (IBE) can be based on the Decisional Diffie-Hellman (DDH) assumption is one of the most prominent questions in Cryptography related to DDH. We study limitations on the use of the DDH assumption in cryptographic constructions, and show that it is impossible to construct a secure ... more >>>

TR12-168 | 26th November 2012
Michael Viderman

An error-correcting code $C \subseteq \F^n$ is called $(q,\epsilon)$-strong locally testable code (LTC) if there exists a randomized algorithm (tester) that makes at most $q$ queries to the input word. This algorithm accepts all codewords with probability 1 and rejects all non-codewords $x\notin C$ with probability at least $\epsilon \cdot ... more >>> TR12-169 | 22nd November 2012 Noga Alon, Santosh Vempala #### The Approximate Rank of a Matrix and its Algorithmic Applications Revisions: 2 We introduce and study the \epsilon-rank of a real matrix A, defi ned, for any  \epsilon > 0 as the minimum rank over matrices that approximate every entry of A to within an additive \epsilon. This parameter is connected to other notions of approximate rank and is motivated by ... more >>> TR12-170 | 30th November 2012 Scott Aaronson, Travis Hance #### Generalizing and Derandomizing Gurvits's Approximation Algorithm for the Permanent Around 2002, Leonid Gurvits gave a striking randomized algorithm to approximate the permanent of an n×n matrix A. The algorithm runs in O(n^2/?^2) time, and approximates Per(A) to within ±?||A||^n additive error. A major advantage of Gurvits's algorithm is that it works for arbitrary matrices, not just for nonnegative matrices. ... more >>> TR12-171 | 3rd December 2012 Mark Braverman, Ankit Garg, Denis Pankratov, Omri Weinstein #### From Information to Exact Communication We develop a new local characterization of the zero-error information complexity function for two party communication problems, and use it to compute the exact internal and external information complexity of the 2-bit AND function:$IC(AND,0) = C_{\wedge}\approx 1.4923$bits, and$IC^{ext}(AND,0) = \log_2 3 \approx 1.5839$bits. This leads to ... more >>> TR12-172 | 8th December 2012 Mahdi Cheraghchi, Anna Gal, Andrew Mills #### Correctness and Corruption of Locally Decodable Codes Locally decodable codes (LDCs) are error correcting codes with the extra property that it is sufficient to read just a small number of positions of a possibly corrupted codeword in order to recover any one position of the input. To achieve this, it is necessary to use randomness in the ... more >>> TR12-173 | 8th December 2012 Kfir Barhum, Thomas Holenstein #### A Cookbook for Black-Box Separations and a Recipe for UOWHFs We present a new framework for proving fully black-box separations and lower bounds. We prove a general theorem that facilitates the proofs of fully black-box lower bounds from a one-way function (OWF). Loosely speaking, our theorem says that in order to prove that a fully black-box construction does ... more >>> TR12-174 | 12th December 2012 Anat Ganor, Ilan Komargodski, Ran Raz #### The Spectrum of Small DeMorgan Formulas Revisions: 1 We show a connection between the deMorgan formula size of a Boolean function and the noise stability of the function. Using this connection, we show that the Fourier spectrum of any balanced Boolean function computed by a deMorgan formula of size$s$is concentrated on coefficients of degree up to ... more >>> TR12-175 | 13th December 2012 James Cook, Omid Etesami, Rachel Miller, Luca Trevisan #### On the One-Way Function Candidate Proposed by Goldreich Revisions: 1 A function$f$mapping$n$-bit strings to$m$-bit strings can be constructed from a bipartite graph with$n$vertices on the left and$m$vertices on the right having right-degree$d$together with a predicate$P:\{0,1\}^d\rightarrow\{0,1\}$. The vertices on the left correspond to the bits of the input to the ... more >>> TR12-176 | 14th December 2012 Marek Karpinski, Andrzej Lingas, Dzmitry Sledneu #### Optimal Cuts and Partitions in Tree Metrics in Polynomial Time We present a polynomial time dynamic programming algorithm for optimal partitions in the shortest path metric induced by a tree. This resolves, among other things, the exact complexity status of the optimal partition problems in one dimensional geometric metric settings. Our method of solution could be also of independent interest ... more >>> TR12-177 | 19th December 2012 Mark Braverman, Ankit Garg, Denis Pankratov, Omri Weinstein #### Information lower bounds via self-reducibility We use self-reduction methods to prove strong information lower bounds on two of the most studied functions in the communication complexity literature: Gap Hamming Distance (GHD) and Inner Product (IP). In our first result we affirm the conjecture that the information cost of GHD is linear even under the uniform ... more >>> TR12-178 | 18th December 2012 Paul Beame, Raphael Clifford, Widad Machmouchi #### Sliding Windows With Limited Storage Revisions: 1 We consider time-space tradeoffs for exactly computing frequency moments and order statistics over sliding windows. Given an input of length$2n-1$, the task is to output the function of each window of length$n$, giving$n$outputs in total. Computations over sliding windows are related to direct sum problems except ... more >>> TR12-179 | 13th December 2012 Joshua Brody, Harry Buhrman, Michal Koucky, Bruno Loff, Florian Speelman #### Towards a Reverse Newman's Theorem in Interactive Information Complexity Revisions: 2 Newman’s theorem states that we can take any public-coin communication protocol and convert it into one that uses only private randomness with only a little increase in communication complexity. We consider a reversed scenario in the context of information complexity: can we take a protocol that uses private randomness and ... more >>> TR12-180 | 21st December 2012 Chaim Even-Zohar, Shachar Lovett #### The Freiman-Ruzsa Theorem in Finite Fields Let$G$be a finite abelian group of torsion$r$and let$A$be a subset of$G$. The Freiman-Ruzsa theorem asserts that if$|A+A| \le K|A|$then$A$is contained in a coset of a subgroup of$G$of size at most$K^2 r^{K^4} |A|$. It was ... more >>> TR12-181 | 20th December 2012 Anindya De, Ilias Diakonikolas, Rocco Servedio #### The Inverse Shapley Value Problem For$f$a weighted voting scheme used by$n$voters to choose between two candidates, the$n$\emph{Shapley-Shubik Indices} (or {\em Shapley values}) of$f$provide a measure of how much control each voter can exert over the overall outcome of the vote. Shapley-Shubik indices were introduced by Lloyd Shapley ... more >>> TR12-182 | 24th December 2012 Itay Berman, Iftach Haitner, Ilan Komargodski, Moni Naor #### Hardness Preserving Reductions via Cuckoo Hashing Revisions: 2 A common method for increasing the usability and uplifting the security of pseudorandom function families (PRFs) is to hash" the inputs into a smaller domain before applying the PRF. This approach, known as Levin's trick", is used to achieve `PRF domain extension" (using a short, e.g., fixed, input length PRF ... more >>> TR12-183 | 25th December 2012 András Salamon #### Streaming bounds from difference ramification Revisions: 1 , Comments: 1 In graph streaming a graph with$n$vertices and$m$edges is presented as a read-once stream of edges. We obtain an$\Omega(n \log n)$lower bound on the space required to decide graph connectivity. This improves the known bounds of$\Omega(n)$for undirected and$\Omega(m)$for sparse directed graphs. ... more >>> TR12-184 | 26th December 2012 Arnab Bhattacharyya, Eldar Fischer, Hamed Hatami, Pooya Hatami, Shachar Lovett #### Every locally characterized affine-invariant property is testable. Revisions: 1 Let$\mathbb{F} = \mathbb{F}_p$for any fixed prime$p \geq 2$. An affine-invariant property is a property of functions on$\mathbb{F}^n$that is closed under taking affine transformations of the domain. We prove that all affine-invariant property having local characterizations are testable. In fact, we show a proximity-oblivious test for ... more >>> TR12-185 | 29th December 2012 Siu Man Chan, Aaron Potechin #### Tight Bounds for Monotone Switching Networks via Fourier Analysis We prove tight size bounds on monotone switching networks for the NP-complete problem of$k$-clique, and for an explicit monotone problem by analyzing a pyramid structure of height$h$for the P-complete problem of generation. This gives alternative proofs of the separations of m-NC from m-P and of m-NC$^i\$ from ... more >>>

TR12-186 | 27th December 2012
Andreas Krebs, Nutan Limaye

#### DLOGTIME-Proof Systems

We define DLOGTIME proof systems, DLTPS, which generalize NC0 proof systems.
It is known that functions such as Exact-k and Majority do not have NC0 proof systems. Here, we give a DLTPS for Exact-k (and therefore for Majority) and also for other natural functions such as Reach and k-Clique. Though ... more >>>

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