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TR17-033 | 19th February 2017
Daniel Kane, Shachar Lovett, Sankeerth Rao

Labeling the complete bipartite graph with no zero cycles

Revisions: 2

Assume that the edges of the complete bipartite graph $K_{n,n}$ are labeled with elements of $\mathbb{F}_2^d$, such that the sum over
any simple cycle is nonzero. What is the smallest possible value of $d$? This problem was raised by Gopalan et al. [SODA 2017] as it characterizes the alphabet size ... more >>>


TR04-002 | 8th January 2004
Troy Lee, Dieter van Melkebeek, Harry Buhrman

Language Compression and Pseudorandom Generators

The language compression problem asks for succinct descriptions of
the strings in a language A such that the strings can be efficiently
recovered from their description when given a membership oracle for
A. We study randomized and nondeterministic decompression schemes
and investigate how close we can get to the information ... more >>>


TR05-152 | 9th December 2005
Oded Lachish, Ilan Newman

Languages that are Recognized by Simple Counter Automata are not necessarily Testable

Combinatorial property testing deals with the following relaxation of
decision problems: Given a fixed property and an input $f$, one wants
to decide whether $f$ satisfies the property or is `far' from satisfying
the property.
It has been shown that regular languages are testable,
and that there exist context free ... more >>>


TR04-014 | 26th November 2003
Chris Pollett

Languages to diagonalize against advice classes

Variants of Kannan's Theorem are given where the circuits of
the original theorem are replaced by arbitrary recursively presentable
classes of languages that use advice strings and satisfy certain mild
conditions. These variants imply that $\DTIME(n^{k'})^{\NE}/n^k$
does not contain $\PTIME^{\NE}$, $\DTIME(2^{n^{k'}})/n^k$ does
not contain $\EXP$, $\SPACE(n^{k'})/n^k$ does not ... more >>>


TR06-117 | 31st August 2006
Arkadev Chattopadhyay, Michal Koucky, Andreas Krebs, Mario Szegedy, Pascal Tesson, Denis Thérien

Languages with Bounded Multiparty Communication Complexity

We study languages with bounded communication complexity in the multiparty "input on the forehead" model with worst-case partition. In the two party case, it is known that such languages are exactly those that are recognized by programs over commutative monoids. This can be used to show that these languages can ... 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 >>>


TR12-042 | 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 >>>


TR11-066 | 25th April 2011
Venkatesan Guruswami, Ali Kemal Sinop

Lasserre Hierarchy, Higher Eigenvalues, and Approximation Schemes for Quadratic Integer Programming with PSD Objectives

Revisions: 1

We present an approximation scheme for optimizing certain Quadratic Integer Programming problems with positive semidefinite objective functions and global linear constraints. This framework includes well known graph problems such as Minimum graph bisection, Edge expansion, Uniform sparsest cut, and Small Set expansion, as well as the Unique Games problem. These ... 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 >>>


TR06-147 | 27th November 2006
Chris Peikert, Alon Rosen

Lattices that Admit Logarithmic Worst-Case to Average-Case Connection Factors

Revisions: 1

We demonstrate an \emph{average-case} problem which is as hard as
finding $\gamma(n)$-approximate shortest vectors in certain
$n$-dimensional lattices in the \emph{worst case}, where $\gamma(n)
= O(\sqrt{\log n})$. The previously best known factor for any class
of lattices was $\gamma(n) = \tilde{O}(n)$.

To obtain our ... more >>>


TR04-113 | 19th November 2004
Mårten Trolin

Lattices with Many Cycles Are Dense

We give a method for approximating any $n$-dimensional
lattice with a lattice $\Lambda$ whose factor group
$\mathbb{Z}^n / \Lambda$ has $n-1$ cycles of equal length
with arbitrary precision. We also show that a direct
consequence of this is that the Shortest Vector Problem and the Closest
Vector Problem cannot ... more >>>


TR14-129 | 10th October 2014
Divesh Aggarwal, Stefan Dziembowski, Tomasz Kazana , Maciej Obremski

Leakage-resilient non-malleable codes

Revisions: 1

A recent trend in cryptography is to construct cryptosystems that are secure against physical attacks. Such attacks are usually divided into two classes: the \emph{leakage} attacks in which the adversary obtains some information about the internal state of the machine, and the \emph{tampering} attacks where the adversary can modify this ... more >>>


TR10-074 | 20th April 2010
Parikshit Gopalan, Rocco Servedio

Learning and Lower Bounds for AC$^0$ with Threshold Gates

In 2002 Jackson et al. [JKS02] asked whether AC0 circuits augmented with a threshold gate at the output can be efficiently learned from uniform random examples. We answer this question affirmatively by showing that such circuits have fairly strong Fourier concentration; hence the low-degree algorithm of Linial, Mansour and Nisan ... more >>>


TR14-144 | 30th October 2014
Eric Blais, Clement Canonne, Igor Carboni Oliveira, Rocco Servedio, Li-Yang Tan

Learning circuits with few negations

Monotone Boolean functions, and the monotone Boolean circuits that compute them, have been intensively studied in complexity theory. In this paper we study the structure of Boolean functions in terms of the minimum number of negations in any circuit computing them, a complexity measure that interpolates between monotone functions and ... more >>>


TR11-115 | 8th August 2011
Varun Kanade, Thomas Steinke

Learning Hurdles for Sleeping Experts

We study the online decision problem where the set of available actions varies over time, also called the sleeping experts problem. We consider the setting where the performance comparison is made with respect to the best ordering of actions in hindsight. In this paper, both the payoff function and the ... more >>>


TR05-088 | 3rd August 2005
Jan Arpe

Learning Juntas in the Presence of Noise

The combination of two major challenges in machine learning is investigated: dealing with large amounts of irrelevant information and learning from noisy data. It is shown that large classes of Boolean concepts that depend on a small number of variables---so-called juntas---can be learned efficiently from random examples corrupted by random ... more >>>


TR96-008 | 22nd January 1996
F. Bergadano, N.H. Bshouty, Stefano Varricchio

Learning Multivariate Polynomials from Substitution and Equivalence Queries

It has been shown in previous recent work that
multiplicity automata are predictable from multiplicity
and equivalence queries. In this paper we generalize
related notions in a matrix representation
and obtain a basis for the solution
of a number of open problems in learnability theory.
Membership queries are generalized ... more >>>


TR00-069 | 14th July 2000
Peter Auer

Learning Nested Differences in the Presence of Malicious Noise

We present a PAC-learning algorithm and an on-line learning algorithm
for nested differences of intersection-closed classes. Examples of
intersection-closed classes include axis-parallel rectangles,
monomials, and linear sub-spaces. Our PAC-learning algorithm uses a
pruning technique that we rigorously proof correct. As a result we
show that ... more >>>


TR00-055 | 14th July 2000
Peter Auer, Stephen Kwek, Manfred K. Warmuth

Learning of Depth Two Neural Networks with Constant Fan-in at the Hidden Nodes

We present algorithms for learning depth two neural networks where the
hidden nodes are threshold gates with constant fan-in. The transfer
function of the output node might be more general: we have results for
the cases when the threshold function, the logistic function or the
identity function is ... more >>>


TR09-060 | 4th June 2009
Harry Buhrman, David García-Soriano, Arie Matsliah

Learning parities in the mistake-bound model.

We study the problem of learning parity functions that depend on at most $k$ variables ($k$-parities) attribute-efficiently in the mistake-bound model.
We design simple, deterministic, polynomial-time algorithms for learning $k$-parities with mistake bound $O(n^{1-\frac{c}{k}})$, for any constant $c > 0$. These are the first polynomial-time algorithms that learn $\omega(1)$-parities in ... more >>>


TR10-066 | 14th April 2010
Sanjeev Arora, Rong Ge

Learning Parities with Structured Noise

Revisions: 1

In the {\em learning parities with noise} problem ---well-studied in learning theory and cryptography--- we
have access to an oracle that, each time we press a button,
returns a random vector $ a \in \GF(2)^n$ together with a bit $b \in \GF(2)$ that was computed as
$a\cdot u +\eta$, where ... more >>>


TR98-060 | 8th October 1998
Oded Goldreich, Ronitt Rubinfeld, Madhu Sudan

Learning polynomials with queries -- The highly noisy case.

This is a revised version of work which has appeared
in preliminary form in the 36th FOCS, 1995.

Given a function $f$ mapping $n$-variate inputs from a finite field
$F$ into $F$,
we consider the task of reconstructing a list of all $n$-variate
degree $d$ polynomials which agree with $f$
more >>>


TR07-129 | 25th October 2007
Jeffrey C. Jackson, Homin Lee, Rocco Servedio, Andrew Wan

Learning Random Monotone DNF

We give an algorithm that with high probability properly learns random monotone t(n)-term
DNF under the uniform distribution on the Boolean cube {0, 1}^n. For any polynomially bounded function t(n) <= poly(n) the algorithm runs in time poly(n, 1/eps) and with high probability outputs an eps accurate monotone DNF ... more >>>


TR17-046 | 8th March 2017
Sebastian Berndt, Maciej Li\'skiewicz, Matthias Lutter, Rüdiger Reischuk

Learning Residual Alternating Automata

Residuality plays an essential role for learning finite automata.
While residual deterministic and nondeterministic
automata have been understood quite well, fundamental
questions concerning alternating automata (AFA) remain open.
Recently, Angluin, Eisenstat, and Fisman have initiated
a systematic study of residual AFAs and proposed an algorithm called AL*
-an extension of ... more >>>


TR10-075 | 22nd April 2010
Ben Reichardt

Least span program witness size equals the general adversary lower bound on quantum query complexity

Span programs form a linear-algebraic model of computation, with span program "size" used in proving classical lower bounds. Quantum query complexity is a coherent generalization, for quantum algorithms, of classical decision-tree complexity. It is bounded below by a semi-definite program (SDP) known as the general adversary bound. We connect these ... more >>>


TR09-062 | 28th July 2009
Daniele Venturi

Lecture Notes on Algorithmic Number Theory

The principal aim of this notes is to give a survey on the state of the art of algorithmic number theory, with particular focus on the theory of elliptic curves.
Computational security is the goal of modern cryptographic constructions: the security of modern criptographic schemes stems from the assumption ... more >>>


TR06-077 | 12th June 2006
Maria Lopez-Valdes

Lempel-Ziv Dimension for Lempel-Ziv Compression

This paper describes the Lempel-Ziv dimension (Hausdorff like
dimension inspired in the LZ78 parsing), its fundamental properties
and relation with Hausdorff dimension.

It is shown that in the case of individual infinite sequences, the
Lempel-Ziv dimension matches with the asymptotical Lempel-Ziv
compression ratio.

This fact is used to describe results ... more >>>


TR05-055 | 19th May 2005
Bruno Codenotti, Amin Saberi, Kasturi Varadarajan, Yinyu Ye

Leontief Economies Encode Nonzero Sum Two-Player Games

We give a reduction from any two-player game to a special case of
the Leontief exchange economy, with the property that the Nash equilibria of the game and the
equilibria of the market are in one-to-one correspondence.

Our reduction exposes a potential hurdle inherent in solving certain
families of market ... more >>>


TR11-168 | 9th December 2011
Joshua Grochow

Lie algebra conjugacy

We study the problem of matrix Lie algebra conjugacy. Lie algebras arise centrally in areas as diverse as differential equations, particle physics, group theory, and the Mulmuley--Sohoni Geometric Complexity Theory program. A matrix Lie algebra is a set $\mathcal{L}$ of matrices such that $A,B \in \mathcal{L}$ implies$AB - BA \in ... more >>>


TR11-097 | 7th July 2011
Thomas Watson

Lift-and-Project Integrality Gaps for the Traveling Salesperson Problem

Revisions: 1

We study the lift-and-project procedures of Lovasz-Schrijver and Sherali-Adams applied to the standard linear programming relaxation of the traveling salesperson problem with triangle inequality. For the asymmetric TSP tour problem, Charikar, Goemans, and Karloff (FOCS 2004) proved that the integrality gap of the standard relaxation is at least 2. We ... more >>>


TR17-165 | 3rd November 2017
Toniann Pitassi, Robert Robere

Lifting Nullstellensatz to Monotone Span Programs over Any Field

We characterize the size of monotone span programs computing certain "structured" boolean functions by the Nullstellensatz degree of a related unsatisfiable Boolean formula.

This yields the first exponential lower bounds for monotone span programs over arbitrary fields, the first exponential separations between monotone span programs over fields of different ... more >>>


TR16-048 | 11th March 2016
Olaf Beyersdorff, Leroy Chew, Renate Schmidt, Martin Suda

Lifting QBF Resolution Calculi to DQBF

We examine the existing Resolution systems for quantified Boolean formulas (QBF) and answer the question which of these calculi can be lifted to the more powerful Dependency QBFs (DQBF). An interesting picture emerges: While for QBF we have the strict chain of proof systems Q-Resolution < IR-calc < IRM-calc, the ... more >>>


TR17-054 | 22nd March 2017
Anurag Anshu, Naresh Goud, Rahul Jain, Srijita Kundu, Priyanka Mukhopadhyay

Lifting randomized query complexity to randomized communication complexity

Revisions: 3

We show that for any (partial) query function $f:\{0,1\}^n\rightarrow \{0,1\}$, the randomized communication complexity of $f$ composed with $\mathrm{Index}^n_m$ (with $m= \poly(n)$) is at least the randomized query complexity of $f$ times $\log n$. Here $\mathrm{Index}_m : [m] \times \{0,1\}^m \rightarrow \{0,1\}$ is defined as $\mathrm{Index}_m(x,y)= y_x$ (the $x$th bit ... more >>>


TR10-123 | 4th August 2010
Eli Ben-Sasson

Limitation on the rate of families of locally testable codes

Revisions: 1

This paper describes recent results which revolve around the question of the rate attainable by families of error correcting codes that are locally testable. Emphasis is placed on motivating the problem of proving upper bounds on the rate of these codes and a number of interesting open questions for future ... more >>>


TR08-007 | 6th February 2008
Dan Gutfreund, Salil Vadhan

Limitations of Hardness vs. Randomness under Uniform Reductions

We consider (uniform) reductions from computing a function f to the task of distinguishing the output of some pseudorandom generator G from uniform. Impagliazzo and Wigderson (FOCS `98, JCSS `01) and Trevisan and Vadhan (CCC `02, CC `07) exhibited such reductions for every function f in PSPACE. Moreover, their reductions ... 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 >>>


TR16-017 | 24th December 2015
Georgios Stamoulis

Limitations of Linear Programming Techniques for Bounded Color Matchings

Given a weighted graph $G = (V,E,w)$, with weight function $w: E \rightarrow \mathbb{Q^+}$, a \textit{matching} $M$ is a set of pairwise non-adjacent edges. In the optimization setting, one seeks to find a matching of \textit{maximum} weight. In the \textit{multi-criteria} (or \textit{multi-budgeted}) setting, we are also given $\ell$ length functions ... 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 >>>


TR11-125 | 16th September 2011
Andrew Drucker

Limitations of Lower-Bound Methods for the Wire Complexity of Boolean Operators

Revisions: 1 , Comments: 1

We study the circuit complexity of Boolean operators, i.e., collections of Boolean functions defined over a common input. Our focus is the well-studied model in which arbitrary Boolean functions are allowed as gates, and in which a circuit's complexity is measured by its depth and number of wires. We show ... more >>>


TR04-026 | 17th February 2004
Scott Aaronson

Limitations of Quantum Advice and One-Way Communication

Although a quantum state requires exponentially many classical bits to describe, the laws of quantum mechanics impose severe restrictions on how that state can be accessed. This paper shows in three settings that quantum messages have only limited advantages over classical ones.
First, we show that BQP/qpoly is contained in ... more >>>


TR15-201 | 10th December 2015
C Ramya, Raghavendra Rao B V

Limitations of sum of products of Read-Once Polynomials

Revisions: 1

We study limitations of polynomials computed by depth two circuits built over read-once polynomials (ROPs) and depth three syntactically multi-linear formulas.
We prove an exponential lower bound for the size of the $\Sigma\Pi^{[N^{1/30}]}$ arithmetic circuits built over syntactically multi-linear $\Sigma\Pi\Sigma^{[N^{8/15}]}$ arithmetic circuits computing a product of variable ... more >>>


TR14-067 | 4th May 2014
Venkatesan Guruswami, Madhu Sudan, Ameya Velingker, Carol Wang

Limitations on Testable Affine-Invariant Codes in the High-Rate Regime

Locally testable codes (LTCs) of constant distance that allow the tester to make a linear number of queries have become the focus of attention recently, due to their elegant connections to hardness of approximation. In particular, the binary Reed-Muller code of block length $N$ and distance $d$ is known to ... more >>>


TR13-055 | 5th April 2013
David Gamarnik, Madhu Sudan

Limits of local algorithms over sparse random graphs

Local algorithms on graphs are algorithms that run in parallel on the nodes of a graph to compute some global structural feature of the graph. Such algorithms use only local information available at nodes to determine local aspects of the global structure, while also potentially using some randomness. Recent research ... more >>>


TR15-198 | 30th November 2015
Shuichi Hirahara, Osamu Watanabe

Limits of Minimum Circuit Size Problem as Oracle

Revisions: 1

The Minimum Circuit Size Problem (MCSP) is known to be hard for statistical zero knowledge via a BPP-reduction (Allender and Das, 2014), whereas establishing NP-hardness of MCSP via a polynomial-time many-one reduction is difficult (Murray and Williams, 2015) in the sense that it implies ZPP $\neq$ EXP, which is a ... 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 >>>


TR12-065 | 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 >>>


TR11-031 | 8th March 2011
Sam Buss, Ryan Williams

Limits on Alternation-Trading Proofs for Time-Space Lower Bounds

This paper characterizes alternation trading based proofs that satisfiability is not in the time and space bounded class $\DTISP(n^c, n^\epsilon)$, for various values $c<2$ and $\epsilon<1$. We characterize exactly what can be proved in the $\epsilon=0$ case with currently known methods, and prove the conjecture of Williams that $c=2\cos(\pi/7)$ is ... more >>>


TR17-060 | 9th April 2017
Boaz Barak, Zvika Brakerski, Ilan Komargodski, Pravesh Kothari

Limits on Low-Degree Pseudorandom Generators (Or: Sum-of-Squares Meets Program Obfuscation)

Revisions: 1

We prove that for every function $G\colon\{0,1\}^n \rightarrow \mathbb{R}^m$, if every output of $G$ is a polynomial (over $\mathbb{R}$) of degree at most $d$ of at most $s$ monomials and $m > \widetilde{O}(sn^{\lceil d/2 \rceil})$, then there is a polynomial time algorithm that can distinguish a vector of the form ... more >>>


TR10-139 | 17th September 2010
Eric Allender, Luke Friedman, William Gasarch

Limits on the Computational Power of Random Strings

Revisions: 1

Let C(x) and K(x) denote plain and prefix Kolmogorov complexity, respectively, and let R_C and R_K denote the sets of strings that are ``random'' according to these measures; both R_K and R_C are undecidable. Earlier work has shown that every set in NEXP is in NP relative to both R_K ... more >>>


TR06-148 | 4th December 2006
Chris Peikert

Limits on the Hardness of Lattice Problems in $\ell_p$ Norms

Revisions: 1

We show that for any $p \geq 2$, lattice problems in the $\ell_p$
norm are subject to all the same limits on hardness as are known
for the $\ell_2$ norm. In particular, for lattices of dimension
$n$:

* Approximating the shortest and closest vector in ... more >>>


TR10-108 | 9th July 2010
Eli Ben-Sasson, Madhu Sudan

Limits on the rate of locally testable affine-invariant codes

A linear code is said to be affine-invariant if the coordinates of the code can be viewed as a vector space and the code is invariant under an affine transformation of the coordinates. A code is said to be locally testable if proximity of a received word
to the code ... more >>>


TR09-068 | 1st September 2009
Dave Buchfuhrer, Chris Umans

Limits on the Social Welfare of Maximal-In-Range Auction Mechanisms

Many commonly-used auction mechanisms are ``maximal-in-range''. We show that any maximal-in-range mechanism for $n$ bidders and $m$ items cannot both approximate the social welfare with a ratio better than $\min(n, m^\eta)$ for any constant $\eta < 1/2$ and run in polynomial time, unless $NP \subseteq P/poly$. This significantly improves upon ... more >>>


TR09-013 | 4th February 2009
Atri Rudra

Limits to List Decoding Random Codes

It has been known since [Zyablov and Pinsker 1982] that a random $q$-ary code of rate $1-H_q(\rho)-\eps$ (where $0<\rho<1-1/q$, $\eps>0$ and $H_q(\cdot)$ is the $q$-ary entropy function) with high probability is a $(\rho,1/\eps)$-list decodable code. (That is, every Hamming ball of radius at most $\rho n$ has at most $1/\eps$ ... more >>>


TR96-005 | 9th January 1996
Hans-Joerg Burtschick, Heribert Vollmer

Lindstroem Quantifiers and Leaf Language Definability

Revisions: 1


We show that examinations of the expressive power of logical formulae
enriched by Lindstroem quantifiers over ordered finite structures
have a well-studied complexity-theoretic counterpart: the leaf
language approach to define complexity classes. Model classes of
formulae with Lindstroem quantifiers are nothing else than leaf
language definable sets. Along the ... more >>>


TR05-042 | 15th April 2005
Lance Fortnow, Adam Klivans

Linear Advice for Randomized Logarithmic Space

Revisions: 1

We show that RL is contained in L/O(n), i.e., any language computable
in randomized logarithmic space can be computed in deterministic
logarithmic space with a linear amount of non-uniform advice. To
prove our result we show how to take an ultra-low space walk on
the Gabber-Galil expander graph.

more >>>

TR01-074 | 12th October 2001
Joshua Buresh-Oppenheim, David Mitchell

Linear and Negative Resolution are Weaker than Resolution

Comments: 1

We prove exponential separations between the sizes of
particular refutations in negative, respectively linear, resolution and
general resolution. Only a superpolynomial separation between negative
and general resolution was previously known. Our examples show that there
is no strong relationship between the size and width of refutations in
negative and ... more >>>


TR07-052 | 7th May 2007
Li Chen, Bin Fu

Linear and Sublinear Time Algorithms for the Basis of Abelian Groups

Revisions: 2

It is well known that every finite Abelian group $G$ can be
represented as a product of cyclic groups: $G=G_1\times
G_2\times\cdots G_t$, where each $G_i$ is a cyclic group of size
$p^j$ for some prime $p$ and integer $j\ge 1$. If $a_i$ is the
generator of the cyclic group of ... more >>>


TR14-141 | 24th October 2014
Shachar Lovett

Linear codes cannot approximate the network capacity within any constant factor

Network coding studies the capacity of networks to carry information, when internal nodes are allowed to actively encode information. It is known that for multi-cast networks, the network coding capacity can be achieved by linear codes. It is also known not to be true for general networks. The best separation ... more >>>


TR99-025 | 2nd July 1999
Yonatan Aumann, Johan Hastad, Michael O. Rabin, Madhu Sudan

Linear Consistency Testing

We extend the notion of linearity testing to the task of checking
linear-consistency of multiple functions. Informally, functions
are ``linear'' if their graphs form straight lines on the plane.
Two such functions are ``consistent'' if the lines have the same
slope. We propose a variant of a test of ... more >>>


TR05-100 | 30th August 2005
David Zuckerman

Linear Degree Extractors and the Inapproximability of Max Clique and Chromatic Number

A randomness extractor is an algorithm which extracts randomness from a low-quality random source, using some additional truly random bits. We construct new extractors which require only log n + O(1) additional random bits for sources with constant entropy rate. We further construct dispersers, which are similar to one-sided extractors, ... more >>>


TR15-017 | 20th January 2015
Bruno Bauwens, Marius Zimand

Linear list-approximation for short programs (or the power of a few random bits)

A $c$-short program for a string $x$ is a description of $x$ of length at most $C(x) + c$, where $C(x)$ is the Kolmogorov complexity of $x$. We show that there exists a randomized algorithm that constructs a list of $n$ elements that contains a $O(\log n)$-short program for $x$. ... more >>>


TR16-182 | 14th November 2016
Rohit Gurjar, Thomas Thierauf

Linear Matroid Intersection is in quasi-NC

Given two matroids on the same ground set, the matroid intersection problem asks to find a common independent set of maximum size. We show that the linear matroid intersection problem is in quasi-NC$^2$. That is, it has uniform circuits of quasi-polynomial size $n^{O(\log n)}$, and $O(\log^2 n)$ depth. This generalizes ... more >>>


TR07-033 | 14th February 2007
Michael Navon, Alex Samorodnitsky

Linear programming bounds for codes via a covering argument

We recover the first linear programming bound of McEliece, Rodemich, Rumsey, and Welch for binary error-correcting codes and designs via a covering argument. It is possible to show, interpreting the following notions appropriately, that if a code has a large distance, then its dual has a small covering radius and, ... more >>>


TR17-086 | 9th May 2017
C Ramya, Raghavendra Rao B V

Linear Projections of the Vandermonde Polynomial

Revisions: 1

An n-variate Vandermonde polynomial is the determinant of the n × n matrix where the ith column is the vector (1, x_i , x_i^2 , . . . , x_i^{n-1})^T. Vandermonde polynomials play a crucial role in the in the theory of alternating polynomials and occur in Lagrangian polynomial interpolation ... more >>>


TR16-174 | 7th November 2016
Elchanan Mossel, Sampath Sampath Kannan, Grigory Yaroslavtsev

Linear Sketching over $\mathbb F_2$

Revisions: 5 , Comments: 2

We initiate a systematic study of linear sketching over $\mathbb F_2$. For a given Boolean function $f \colon \{0,1\}^n \to \{0,1\}$ a randomized $\mathbb F_2$-sketch is a distribution $\mathcal M$ over $d \times n$ matrices with elements over $\mathbb F_2$ such that $\mathcal Mx$ suffices for computing $f(x)$ with high ... more >>>


TR11-048 | 10th April 2011
Arkadev Chattopadhyay, Shachar Lovett

Linear systems over abelian groups

We consider a system of linear constraints over any finite Abelian group $G$ of the following form: $\ell_i(x_1,\ldots,x_n) \equiv \ell_{i,1}x_1+\cdots+\ell_{i,n}x_n \in A_i$ for $i=1,\ldots,t$ and each $A_i \subset G$, $\ell_{i,j}$ is an element of $G$ and $x_i$'s are Boolean variables. Our main result shows that the subset of the Boolean ... more >>>


TR09-084 | 24th September 2009
Arkadev Chattopadhyay, Avi Wigderson

Linear systems over composite moduli

We study solution sets to systems of generalized linear equations of the following form:
$\ell_i (x_1, x_2, \cdots , x_n)\, \in \,A_i \,\, (\text{mod } m)$,
where $\ell_1, \ldots ,\ell_t$ are linear forms in $n$ Boolean variables, each $A_i$ is an arbitrary subset of $\mathbb{Z}_m$, and $m$ is a composite ... more >>>


TR08-101 | 20th November 2008
Marek Karpinski, Warren Schudy

Linear Time Approximation Schemes for the Gale-Berlekamp Game and Related Minimization Problems

We design a linear time approximation scheme for the Gale-Berlekamp Switching Game and generalize it to a wider class of dense fragile minimization problems including the Nearest Codeword Problem (NCP) and Unique Games Problem. Further applications include, among other things, finding a constrained form of matrix rigidity and maximum likelihood ... more >>>


TR11-058 | 15th April 2011
Michael Viderman

Linear time decoding of regular expander codes

Revisions: 1

Sipser and Spielman (IEEE IT, 1996) showed that any $(c,d)$-regular expander code with expansion parameter $> \frac{3}{4}$ is decodable in \emph{linear time} from a constant fraction of errors. Feldman et al. (IEEE IT, 2007)
proved that expansion parameter $> \frac{2}{3} + \frac{1}{3c}$ is sufficient to correct a constant fraction of ... more >>>


TR04-016 | 3rd March 2004
Michael Alekhnovich, Eli Ben-Sasson

Linear Upper Bounds for Random Walk on Small Density Random 3CNFs

We analyze the efficiency of the random walk algorithm on random 3CNF instances, and prove em linear upper bounds on the running time
of this algorithm for small clause density, less than 1.63. Our upper bound matches the observed running time to within a multiplicative factor. This is the ... 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 >>>


TR14-015 | 24th January 2014
Jack H. Lutz, Neil Lutz

Lines Missing Every Random Point

Revisions: 1

This paper proves that there is, in every direction in Euclidean space, a line that misses every computably random point. Our proof of this fact shows that a famous set constructed by Besicovitch in 1964 has computable measure 0.

more >>>

TR14-007 | 17th January 2014
Mark Braverman, Klim Efremenko

List and Unique Coding for Interactive Communication in the Presence of Adversarial Noise

In this paper we extend the notion of list decoding to the setting of interactive communication and study its limits. In particular, we show that any protocol can be encoded, with a constant rate, into a list-decodable protocol which is resilient
to a noise rate of up to $1/2-\varepsilon$, ... more >>>


TR11-165 | 8th December 2011
Elena Grigorescu, Chris Peikert

List Decoding Barnes-Wall Lattices

Revisions: 2

The question of list decoding error-correcting codes over finite fields (under the Hamming metric) has been widely studied in recent years. Motivated by the similar discrete structure of linear codes and point lattices in $R^{N}$, and their many shared applications across complexity theory, cryptography, and coding theory, we initiate the ... more >>>


TR14-087 | 12th July 2014
Abhishek Bhowmick, Shachar Lovett

List decoding Reed-Muller codes over small fields

Revisions: 1

The list decoding problem for a code asks for the maximal radius up to which any ball of that radius contains only a constant number of codewords. The list decoding radius is not well understood even for well studied codes, like Reed-Solomon or Reed-Muller codes.

Fix a finite field $\mathbb{F}$. ... 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 >>>


TR08-105 | 26th November 2008
Parikshit Gopalan, Venkatesan Guruswami, Prasad Raghavendra, Prasad Raghavendra

List Decoding Tensor Products and Interleaved Codes

We design the first efficient algorithms and prove new combinatorial bounds for list decoding tensor products of codes and interleaved codes.

1)We show that for every code, the ratio of its list decoding radius to its minimum distance stays unchanged under the tensor product operation (rather than squaring, as one ... more >>>


TR03-042 | 15th May 2003
Luca Trevisan

List Decoding Using the XOR Lemma

We show that Yao's XOR Lemma, and its essentially equivalent
rephrasing as a Direct Product Lemma, can be
re-interpreted as a way of obtaining error-correcting
codes with good list-decoding algorithms from error-correcting
codes having weak unique-decoding algorithms. To get codes
with good rate and efficient list decoding algorithms
one needs ... more >>>


TR02-024 | 24th April 2002
Piotr Indyk

List-decoding in Linear Time

Spielman showed that one can construct error-correcting codes capable
of correcting a constant fraction $\delta << 1/2$ of errors,
and that are encodable/decodable in linear time.
Guruswami and Sudan showed that it is possible to correct
more than $50\%$ of errors (and thus exceed the ``half of the ... 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 >>>


TR11-020 | 20th December 2010
Yijia Chen, Joerg Flum

Listings and logics

There are standard logics DTC, TC, and LFP capturing the complexity classes L, NL, and P on ordered structures, respectively. In [Chen and Flum, 2010] we have shown that ${\rm LFP}_{\rm inv}$, the ``order-invariant least fixed-point logic LFP,'' captures P (on all finite structures) if and only if there is ... more >>>


TR15-038 | 11th March 2015
Gil Cohen

Local Correlation Breakers and Applications to Three-Source Extractors and Mergers

Revisions: 1

We introduce and construct a pseudorandom object which we call a local correlation breaker (LCB). Informally speaking, an LCB is a function that gets as input a sequence of $r$ (arbitrarily correlated) random variables and an independent weak-source. The output of the LCB is a sequence of $r$ random variables ... more >>>


TR17-138 | 17th September 2017
Srikanth Srinivasan, Madhu Sudan

Local decoding and testing of polynomials over grids

The well-known DeMillo-Lipton-Schwartz-Zippel lemma says that $n$-variate
polynomials of total degree at most $d$ over
grids, i.e. sets of the form $A_1 \times A_2 \times \cdots \times A_n$, form
error-correcting codes (of distance at least $2^{-d}$ provided $\min_i\{|A_i|\}\geq 2$).
In this work we explore their local
decodability and local testability. ... more >>>


TR16-129 | 16th August 2016
Emanuele Viola, Avi Wigderson

Local Expanders

Revisions: 1

Abstract A map $f:{0,1}^{n}\to {0,1}^{n}$ has locality t if every output bit of f depends only on t input bits. Arora, Steurer, and Wigderson (2009) ask if there exist bounded-degree expander graphs on $2^{n}$ nodes such that the neighbors of a node $x\in {0,1}^{n}$ can be computed by maps of ... more >>>


TR07-108 | 27th October 2007
Moses Charikar, Konstantin Makarychev, Yury Makarychev

Local Global Tradeoffs in Metric Embeddings

Suppose that every k points in a n point metric space X are D-distortion embeddable into l_1. We give upper and lower bounds on the distortion required to embed the entire space X into l_1. This is a natural mathematical question and is also motivated by the study of relaxations ... more >>>


TR10-047 | 23rd March 2010
Avraham Ben-Aroya, Klim Efremenko, Amnon Ta-Shma

Local list decoding with a constant number of queries

Revisions: 1

Recently Efremenko showed locally-decodable codes of sub-exponential
length. That result showed that these codes can handle up to
$\frac{1}{3} $ fraction of errors. In this paper we show that the
same codes can be locally unique-decoded from error rate
$\half-\alpha$ for any $\alpha>0$ and locally list-decoded from
error rate $1-\alpha$ ... more >>>


TR17-104 | 13th June 2017
Brett Hemenway, Noga Ron-Zewi, Mary Wootters

Local List Recovery of High-rate Tensor Codes & Applications

In this work, we give the first construction of {\em high-rate} locally list-recoverable codes. List-recovery has been an extremely useful building block in coding theory, and our motivation is to use these codes as such a building block.
In particular, our construction gives the first {\em capacity-achieving} locally list-decodable ... more >>>


TR09-115 | 13th November 2009
Swastik Kopparty, Shubhangi Saraf

Local list-decoding and testing of random linear codes from high-error


In this paper, we give surprisingly efficient algorithms for list-decoding and testing
{\em random} linear codes. Our main result is that random sparse linear codes are locally testable and locally list-decodable
in the {\em high-error} regime with only a {\em constant} number of queries.
More precisely, we show that ... more >>>


TR16-163 | 25th October 2016
Matthew Hastings

Local Maxima and Improved Exact Algorithm for MAX-2-SAT

Given a MAX-2-SAT instance, we define a local maximum to be an assignment such that changing any single variable reduces the number of satisfied clauses. We consider the question of the number of local maxima hat an instance of MAX-2-SAT can have. We give upper bounds in both the sparse ... more >>>


TR15-128 | 10th August 2015
Roee David, Elazar Goldenberg, Robert Krauthgamer

Local Reconstruction of Low-Rank Matrices and Subspaces

Revisions: 2

We study the problem of \emph{reconstructing a low-rank matrix}, where the input is an $n\times m$ matrix $M$ over a field $\mathbb{F}$ and the goal is to reconstruct a (near-optimal) matrix $M'$ that is low-rank and close to $M$ under some distance function $\Delta$.
Furthermore, the reconstruction must be local, ... more >>>


TR13-099 | 6th July 2013
Hamidreza Jahanjou, Eric Miles, Emanuele Viola

Local reductions

Revisions: 3

We reduce non-deterministic time $T \ge 2^n$ to a 3SAT
instance $\phi$ of size $|\phi| = T \cdot \log^{O(1)} T$
such that there is an explicit circuit $C$ that on input
an index $i$ of $\log |\phi|$ bits outputs the $i$th
clause, and each output bit of $C$ depends on ... more >>>


TR17-126 | 7th August 2017
Swastik Kopparty, Shubhangi Saraf

Local Testing and Decoding of High-Rate Error-Correcting Codes

We survey the state of the art in constructions of locally testable
codes, locally decodable codes and locally correctable codes of high rate.

more >>>

TR16-125 | 31st July 2016
Karthekeyan Chandrasekaran, Mahdi Cheraghchi, Venkata Gandikota, Elena Grigorescu

Local Testing for Membership in Lattices

Motivated by the structural analogies between point lattices and linear error-correcting codes, and by the mature theory on locally testable codes, we initiate a systematic study of local testing for membership in lattices. Testing membership in lattices is also motivated in practice, by applications to integer programming, error detection in ... more >>>


TR11-158 | 25th November 2011
Matthew Anderson, Dieter van Melkebeek, Nicole Schweikardt, Luc Segoufin

Locality from Circuit Lower Bounds

We study the locality of an extension of first-order logic that captures graph queries computable in AC$^0$, i.e., by families of polynomial-size constant-depth circuits. The extension considers first-order formulas over relational structures which may use arbitrary numerical predicates in such a way that their truth value is independent of the ... more >>>


TR13-098 | 28th June 2013
Benny Applebaum, Yoni Moses

Locally Computable UOWHF with Linear Shrinkage

We study the problem of constructing locally computable Universal One-Way Hash Functions (UOWHFs) $H:\{0,1\}^n \rightarrow \{0,1\}^m$. A construction with constant \emph{output locality}, where every bit of the output depends only on a constant number of bits of the input, was established by [Applebaum, Ishai, and Kushilevitz, SICOMP 2006]. However, this ... more >>>


TR03-046 | 11th June 2003
Philippe Moser

Locally Computed Baire's Categories on Small Complexity Classes

We strengthen an earlier notion of
resource-bounded Baire's categories, and define
resource bounded Baire's categories on small complexity classes such as P, QP, SUBEXP
and on probabilistic complexity classes such as BPP.
We give an alternative characterization of meager sets via resource-bounded
Banach Mazur games.
We show that the class ... more >>>


TR04-051 | 10th June 2004
Zdenek Dvorák, Daniel Král, Ondrej Pangrác

Locally consistent constraint satisfaction problems

An instance of a constraint satisfaction problem is $l$-consistent
if any $l$ constraints of it can be simultaneously satisfied.
For a set $\Pi$ of constraint types, $\rho_l(\Pi)$ denotes the largest ratio of constraints which can be satisfied in any $l$-consistent instance composed by constraints from the set $\Pi$. In the ... more >>>


TR14-107 | 10th August 2014
Or Meir

Locally Correctable and Testable Codes Approaching the Singleton Bound

Revisions: 2

Locally-correctable codes (LCCs) and locally-testable codes (LTCs) are codes that admit local algorithms for decoding and testing respectively. The local algorithms are randomized algorithms that make only a small number of queries to their input. LCCs and LTCs are both interesting in their own right, and have important applications in ... more >>>


TR07-040 | 12th April 2007
Kiran Kedlaya, Sergey Yekhanin

Locally Decodable Codes From Nice Subsets of Finite Fields and Prime Factors of Mersenne Numbers

A k-query Locally Decodable Code (LDC) encodes an n-bit message x as an N-bit codeword C(x), such that one can probabilistically recover any bit x_i of the message by querying only k bits of the codeword C(x), even after some constant fraction of codeword bits has been corrupted. The major ... more >>>


TR05-044 | 6th April 2005
Zeev Dvir, Amir Shpilka

Locally Decodable Codes with 2 queries and Polynomial Identity Testing for depth 3 circuits

In this work we study two seemingly unrelated notions. Locally Decodable Codes(LDCs) are codes that allow the recovery of each message bit from a constant number of entries of the codeword. Polynomial Identity Testing (PIT) is one of the fundamental problems of algebraic complexity: we are given a circuit computing ... more >>>


TR13-115 | 27th August 2013
Daniele Micciancio

Locally Dense Codes

The Minimum Distance Problem (MDP), i.e., the computational task of evaluating (exactly or approximately) the minimum distance of a linear code, is a well known NP-hard problem in coding theory. A key element in essentially all known proofs that MDP is NP-hard is the construction of a combinatorial object that ... more >>>


TR03-050 | 16th June 2003
Daniel Král

Locally satisfiable formulas

A CNF formula is k-satisfiable if each k clauses of it can be satisfied
simultaneously. Let \pi_k be the largest real number such that for each
k-satisfiable formula with variables x_i, there are probabilities p_i
with the following property: If each variable x_i is chosen randomly and
independently to be ... more >>>


TR16-122 | 11th August 2016
Sivakanth Gopi, Swastik Kopparty, Rafael Mendes de Oliveira, Noga Ron-Zewi, Shubhangi Saraf

Locally testable and Locally correctable Codes Approaching the Gilbert-Varshamov Bound

One of the most important open problems in the theory
of error-correcting codes is to determine the
tradeoff between the rate $R$ and minimum distance $\delta$ of a binary
code. The best known tradeoff is the Gilbert-Varshamov bound,
and says that for every $\delta \in (0, 1/2)$, there are ... more >>>


TR09-128 | 29th November 2009
Gillat Kol, Ran Raz

Locally Testable Codes Analogues to the Unique Games Conjecture Do Not Exist

The Unique Games Conjecture (UGC) is possibly the most important open problem in the research of PCPs and hardness of approximation. The conjecture is a strengthening of the PCP Theorem, predicting the existence of a special type of PCP verifiers: 2-query verifiers that only make unique tests. Moreover, the UGC ... more >>>


TR13-114 | 24th August 2013
Parikshit Gopalan, Salil Vadhan, Yuan Zhou

Locally Testable Codes and Cayley Graphs

Revisions: 1

We give two new characterizations of ($\F_2$-linear) locally testable error-correcting codes in terms of Cayley graphs over $\F_2^h$:

\begin{enumerate}
\item A locally testable code is equivalent to a Cayley graph over $\F_2^h$ whose set of generators is significantly larger than $h$ and has no short linear dependencies, but yields a ... more >>>


TR02-050 | 5th August 2002
Oded Goldreich, Madhu Sudan

Locally Testable Codes and PCPs of Almost-Linear Length

Locally testable codes are error-correcting codes that admit
very efficient codeword tests. Specifically, using a constant
number of (random) queries, non-codewords are rejected with
probability proportional to their distance from the code.

Locally testable codes are believed to be the combinatorial
core of PCPs. However, the relation is ... more >>>


TR09-126 | 26th November 2009
Eli Ben-Sasson, Venkatesan Guruswami, Tali Kaufman, Madhu Sudan, Michael Viderman

Locally Testable Codes Require Redundant Testers

Revisions: 3

Locally testable codes (LTCs) are error-correcting codes for which membership, in the code, of a given word can be tested by examining it in very few locations. Most known constructions of locally testable codes are linear codes, and give error-correcting codes
whose duals have (superlinearly) {\em many} small weight ... more >>>


TR10-130 | 18th August 2010
Tali Kaufman, Michael Viderman

Locally Testable vs. Locally Decodable Codes

Revisions: 1

We study the relation between locally testable and locally decodable codes.
Locally testable codes (LTCs) are error-correcting codes for which membership of a given word in the code can be tested probabilistically by examining it in very few locations. Locally decodable codes (LDCs) allow to recover each message entry with ... more >>>


TR01-013 | 2nd February 2001
Michal Koucky

Log-space Constructible Universal Traversal Sequences for Cycles of Length $O(n^{4.03})$

The paper presents a simple construction of polynomial length universal
traversal sequences for cycles. These universal traversal sequences are
log-space (even $NC^1$) constructible and are of length $O(n^{4.03})$. Our
result improves the previously known upper-bound $O(n^{4.76})$ for
log-space constructible universal traversal sequences for cycles.

more >>>

TR07-091 | 10th September 2007
Martin Grohe

Logic, Graphs, and Algorithms

Algorithmic meta theorems are algorithmic results that apply to whole families of combinatorial problems, instead of just specific problems. These families are usually defined in terms of logic and graph theory. An archetypal algorithmic meta theorem is Courcelle's Theorem, which states that all graph properties definable in monadic second-order logic ... more >>>


TR16-154 | 21st September 2016
Scott Garrabrant, Tsvi Benson-Tilsen, Andrew Critch, Nate Soares, Jessica Taylor

Logical Induction

We present a computable algorithm that assigns probabilities to every logical statement in a given formal language, and refines those probabilities over time. For instance, if the language is Peano arithmetic, it assigns probabilities to all arithmetical statements, including claims about the twin prime conjecture, the outputs of long-running ... more >>>


TR01-088 | 29th October 2001
Alexander Shen, Nikolay Vereshchagin

Logical operations and Kolmogorov complexity

We define Kolmogorov complexity of a set of strings as the minimal
Kolmogorov complexity of its element. Consider three logical
operations on sets going back to Kolmogorov
and Kleene:
(A OR B) is the direct sum of A,B,
(A AND B) is the cartesian product of A,B,
more >>>


TR01-089 | 29th October 2001
Andrej Muchnik, Nikolay Vereshchagin

Logical operations and Kolmogorov complexity. II

We invistigate what is the minimal length of
a program mapping A to B and at the same time
mapping C to D (where A,B,C,D are binary strings). We prove that
it cannot be expressed
in terms of Kolmogorv complexity of A,B,C,D, their pairs (A,B), (A,C),
..., their ... more >>>


TR03-077 | 4th September 2003
Till Tantau

Logspace Optimisation Problems and their Approximation Properties

This paper introduces logspace optimisation problems as
analogues of the well-studied polynomial-time optimisation
problems. Similarly to them, logspace
optimisation problems can have vastly different approximation
properties, even though the underlying existence and budget problems
have the same computational complexity. Numerous natural problems
are presented that exhibit such a varying ... more >>>


TR09-050 | 28th May 2009
Jan Kyncl, Tomas Vyskocil

Logspace reduction of directed reachability for bounded genus graphs to the planar case

Directed reachability (or briefly reachability) is the following decision problem: given a directed graph G and two of its vertices s,t, determine whether there is a directed path from s to t in G. Directed reachability is a standard complete problem for the complexity class NL. Planar reachability is an ... more >>>


TR10-062 | 7th April 2010
Michael Elberfeld, Andreas Jakoby, Till Tantau

Logspace Versions of the Theorems of Bodlaender and Courcelle

Bodlaender's Theorem states that for every $k$ there is a linear-time algorithm that decides whether an input graph has tree width~$k$ and, if so, computes a width-$k$ tree composition. Courcelle's Theorem builds on Bodlaender's Theorem and states that for every monadic second-order formula $\phi$ and for
every $k$ there is ... more >>>


TR96-060 | 19th November 1996
Bernd Borchert, Frank Stephan

Looking for an Analogue of Rice's Theorem in Complexity Theory

Rice's Theorem says that every nontrivial semantic property
of programs is undecidable. It this spirit we show the following:
Every nontrivial absolute (gap, relative) counting property of circuits
is UP-hard with respect to polynomial-time Turing reductions.

more >>>

TR07-080 | 7th August 2007
Chris Peikert, Brent Waters

Lossy Trapdoor Functions and Their Applications

We propose a new general primitive called lossy trapdoor
functions (lossy TDFs), and realize it under a variety of different
number theoretic assumptions, including hardness of the decisional
Diffie-Hellman (DDH) problem and the worst-case hardness of
standard lattice problems.

Using lossy TDFs, we develop a new approach for constructing ... more >>>


TR09-127 | 25th November 2009
Brett Hemenway, Rafail Ostrovsky

Lossy Trapdoor Functions from Smooth Homomorphic Hash Proof Systems

Revisions: 2

In STOC '08, Peikert and Waters introduced a powerful new primitive called Lossy Trapdoor Functions (LTDFs). Since their introduction, lossy trapdoor functions have found many uses in cryptography. In the work of Peikert and Waters, lossy trapdoor functions were used to give an efficient construction of a chosen-ciphertext secure ... more >>>


TR17-180 | 26th November 2017
Irit Dinur, Yuval Filmus, Prahladh Harsha

Low degree almost Boolean functions are sparse juntas

Nisan and Szegedy showed that low degree Boolean functions are juntas. Kindler and Safra showed that low degree functions which are *almost* Boolean are close to juntas. Their result holds with respect to $\mu_p$ for every *constant* $p$. When $p$ is allowed to be very small, new phenomena emerge. ... more >>>


TR15-111 | 8th July 2015
Diptarka Chakraborty, Elazar Goldenberg, Michal Koucky

Low Distortion Embedding from Edit to Hamming Distance using Coupling

Revisions: 1


The Hamming and the edit metrics are two common notions of measuring distances between pairs of strings $x,y$ lying in the Boolean hypercube. The edit distance between $x$ and $y$ is defined as the minimum number of character insertion, deletion, and bit flips needed for converting $x$ into $y$. ... more >>>


TR10-004 | 6th January 2010
Eli Ben-Sasson, Michael Viderman

Low Rate Is Insufficient for Local Testability

Revisions: 3

Locally testable codes (LTCs) are error-correcting codes for which membership of a given word in the code can be tested probabilistically by examining it in very few locations.
Kaufman and Sudan \cite{KS07} proved that sparse, low-bias linear codes are locally testable (in particular sparse random codes are locally testable).
Kopparty ... more >>>


TR11-095 | 22nd June 2011
Christoph Behle, Andreas Krebs, Klaus-Joern Lange, Pierre McKenzie

Low uniform versions of NC1

Revisions: 1

In the setting known as DLOGTIME-uniformity,
the fundamental complexity classes
$AC^0\subset ACC^0\subseteq TC^0\subseteq NC^1$ have several
robust characterizations.
In this paper we refine uniformity further and examine the impact
of these refinements on $NC^1$ and its subclasses.
When applied to the logarithmic circuit depth characterization of $NC^1$,
some refinements leave ... more >>>


TR17-008 | 14th January 2017
Benny Applebaum, Naama Haramaty, Yuval Ishai, Eyal Kushilevitz, Vinod Vaikuntanathan

Low-Complexity Cryptographic Hash Functions

Cryptographic hash functions are efficiently computable functions that shrink a long input into a shorter output while achieving some of the useful security properties of a random function. The most common type of such hash functions is {\em collision resistant} hash functions (CRH), which prevent an efficient attacker from finding ... more >>>


TR06-054 | 16th April 2006
Alex Samorodnitsky

Low-degree tests at large distances

We define tests of boolean functions which
distinguish between linear (or quadratic) polynomials, and functions
which are very far, in an appropriate sense, from these
polynomials. The tests have optimal or nearly optimal trade-offs
between soundness and the number of queries.

In particular, we show that functions with small ... more >>>


TR13-177 | 10th December 2013
Eric Allender, Nikhil Balaji, Samir Datta

Low-depth Uniform Threshold Circuits and the Bit-Complexity of Straight Line Programs

Revisions: 1

We present improved uniform TC$^0$ circuits for division, matrix powering, and related problems, where the improvement is in terms of ``majority depth'' (initially studied by Maciel and Therien). As a corollary, we obtain improved bounds on the complexity of certain problems involving arithmetic circuits, which are known to lie in ... more >>>


TR06-125 | 20th September 2006
Luis Antunes, Lance Fortnow, Alexandre Pinto, Andre Souto

Low-Depth Witnesses are Easy to Find

Antunes, Fortnow, van Melkebeek and Vinodchandran captured the
notion of non-random information by computational depth, the
difference between the polynomial-time-bounded Kolmogorov
complexity and traditional Kolmogorov complexity We show how to
find satisfying assignments for formulas that have at least one
assignment of logarithmic depth. The converse holds under a
standard ... more >>>


TR07-069 | 29th July 2007
Ronen Shaltiel, Chris Umans

Low-end uniform hardness vs. randomness tradeoffs for AM

In 1998, Impagliazzo and Wigderson proved a hardness vs. randomness tradeoff for BPP in the {\em uniform setting}, which was subsequently extended to give optimal tradeoffs for the full range of possible hardness assumptions by Trevisan and Vadhan (in a slightly weaker setting). In 2003, Gutfreund, Shaltiel and Ta-Shma proved ... more >>>


TR16-106 | 15th July 2016
Avraham Ben-Aroya, Dean Doron, Amnon Ta-Shma

Low-error two-source extractors for polynomial min-entropy

Revisions: 1

We construct explicit two-source extractors for $n$ bit sources,
requiring $n^\alpha$ min-entropy and having error $2^{-n^\beta}$,
for some constants $0 < \alpha,\beta < 1$. Previously, constructions
for exponentially small error required either min-entropy
$0.49n$ \cite{Bou05} or three sources \cite{Li15}. The construction
combines somewhere-random condensers based on the Incidence
Theorem \cite{Zuc06,Li11}, ... more >>>


TR16-084 | 23rd May 2016
Shalev Ben-David

Low-Sensitivity Functions from Unambiguous Certificates

We provide new query complexity separations against sensitivity for total Boolean functions: a power 3 separation between deterministic (and even randomized or quantum) query complexity and sensitivity, and a power 2.1 separation between certificate complexity and sensitivity. We get these separations by using a new connection between sensitivity and a ... more >>>


TR15-139 | 25th August 2015
Eli Ben-Sasson, Gal Maor

Lower bound for communication complexity with no public randomness

We give a self contained proof of a logarithmic lower bound on the communication complexity of any non redundant function, given that there is no access to shared randomness. This bound was first stated in Yao's seminal paper [STOC 1979], but no full proof appears in the literature.

Our proof ... more >>>


TR16-153 | 28th September 2016
Christian Engels, Raghavendra Rao B V, Karteek Sreenivasaiah

Lower Bounds and Identity Testing for Projections of Power Symmetric Polynomials

Revisions: 3

The power symmetric polynomial on $n$ variables of degree $d$ is defined as
$p_d(x_1,\ldots, x_n) = x_{1}^{d}+\dots + x_{n}^{d}$. We study polynomials that are expressible as a sum of powers
of homogenous linear projections of power symmetric polynomials. These form a subclass of polynomials computed by
... 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 >>>


TR10-022 | 23rd February 2010
Vitaly Feldman, Homin Lee, Rocco Servedio

Lower Bounds and Hardness Amplification for Learning Shallow Monotone Formulas

Much work has been done on learning various classes of ``simple'' monotone functions under the uniform distribution. In this paper we give the first unconditional lower bounds for learning problems of this sort by showing that polynomial-time algorithms cannot learn constant-depth monotone Boolean formulas under the uniform distribution in the ... more >>>


TR17-077 | 30th April 2017
Guillaume Lagarde, Nutan Limaye, Srikanth Srinivasan

Lower Bounds and PIT for Non-Commutative Arithmetic circuits with Restricted Parse Trees

We investigate the power of Non-commutative Arithmetic Circuits, which compute polynomials over the free non-commutative polynomial ring $\mathbb{F}\langle x_1,\dots,x_N \rangle$, where variables do not commute. We consider circuits that are restricted in the ways in which they can compute monomials: this can be seen as restricting the families of parse ... more >>>


TR08-006 | 18th January 2008
Ran Raz, Amir Yehudayoff

Lower Bounds and Separations for Constant Depth Multilinear Circuits

We prove an exponential lower bound for the size of constant depth multilinear arithmetic circuits computing either the determinant or the permanent (a circuit is called multilinear, if the polynomial computed by each of its gates is multilinear). We also prove a super-polynomial separation between the size of product-depth $d$ ... more >>>


TR98-036 | 11th June 1998
Vince Grolmusz, Gábor Tardos

Lower Bounds for (MOD p -- MOD m) Circuits

Modular gates are known to be immune for the random
restriction techniques of Ajtai; Furst, Saxe, Sipser; and Yao and
Hastad. We demonstrate here a random clustering technique which
overcomes this difficulty and is capable to prove generalizations of
several known modular circuit lower bounds of Barrington, Straubing,
Therien; Krause ... more >>>


TR16-189 | 21st November 2016
Arnab Bhattacharyya, Sivakanth Gopi

Lower bounds for 2-query LCCs over large alphabet

A locally correctable code (LCC) is an error correcting code that allows correction of any arbitrary coordinate of a corrupted codeword by querying only a few coordinates.
We show that any zero-error $2$-query locally correctable code $\mathcal{C}: \{0,1\}^k \to \Sigma^n$ that can correct a constant fraction of corrupted symbols must ... more >>>


TR16-107 | 17th July 2016
Nathanael Fijalkow

Lower Bounds for Alternating Online Space Complexity

Revisions: 1

The notion of online space complexity, introduced by Karp in 1967, quantifies the amount of states required to solve a given problem using an online algorithm,
represented by a machine which scans the input exactly once from left to right.
In this paper, we study alternating machines as introduced by ... more >>>


TR14-026 | 27th February 2014
Jop Briet, Zeev Dvir, Guangda Hu, Shubhangi Saraf

Lower Bounds for Approximate LDCs

We study an approximate version of $q$-query LDCs (Locally Decodable Codes) over the real numbers and prove lower bounds on the encoding length of such codes. A $q$-query $(\alpha,\delta)$-approximate LDC is a set $V$ of $n$ points in $\mathbb{R}^d$ so that, for each $i \in [d]$ there are $\Omega(\delta n)$ ... more >>>


TR17-185 | 28th November 2017
Makrand Sinha

Lower Bounds for Approximating the Matching Polytope

We prove that any extended formulation that approximates the matching polytope on $n$-vertex graphs up to a factor of $(1+\varepsilon)$ for any $\frac2n \le \varepsilon \le 1$ must have at least ${n}\choose{{\alpha}/{\varepsilon}}$ defining inequalities where $0<\alpha<1$ is an absolute constant. This is tight as exhibited by the $(1+\varepsilon)$ approximating linear ... more >>>


TR08-032 | 18th March 2008
Dmitriy Cherukhin

Lower Bounds for Boolean Circuits with Finite Depth and Arbitrary Gates

We consider bounded depth circuits over an arbitrary field $K$. If the field $K$ is finite, then we allow arbitrary gates $K^n\to K$. For instance, in the case of field $GF(2)$ we allow any Boolean gates. If the field $K$ is infinite, then we allow only polinomials.

For every fixed ... more >>>


TR03-004 | 24th December 2002
Eli Ben-Sasson, Prahladh Harsha

Lower Bounds for Bounded-Depth Frege Proofs via Buss-Pudlack Games

We present a simple proof of the bounded-depth Frege lower bounds of
Pitassi et. al. and Krajicek et. al. for the pigeonhole
principle. Our method uses the interpretation of proofs as two player
games given by Pudlak and Buss. Our lower bound is conceptually
simpler than previous ones, and relies ... more >>>


TR06-079 | 12th June 2006
Kristoffer Arnsfelt Hansen

Lower Bounds for Circuits with Few Modular Gates using Exponential Sums

We prove that any AC0 circuit augmented with {epsilon log^2 n}
MOD_m gates and with a MAJORITY gate at the output, require size
n^{Omega(log n)} to compute MOD_l, when l has a prime
factor not dividing m and epsilon is sufficiently small. We
also obtain ... more >>>


TR95-027 | 30th May 1995
Frederic Green

Lower Bounds for Circuits with Mod Gates and One Exact Threshold Gate

We say an integer polynomial $p$, on Boolean inputs, weakly
$m$-represents a Boolean function $f$ if $p$ is non-constant and is zero (mod
$m$), whenever $f$ is zero. In this paper we prove that if a polynomial
weakly $m$-represents the Mod$_q$ function on $n$ inputs, where $q$ and $m$
more >>>


TR15-012 | 24th January 2015
Mika Göös

Lower Bounds for Clique vs. Independent Set

We prove an $\omega(\log n)$ lower bound on the conondeterministic communication complexity of the Clique vs. Independent Set problem introduced by Yannakakis (STOC 1988, JCSS 1991). As a corollary, this implies superpolynomial lower bounds for the Alon--Saks--Seymour conjecture in graph theory. Our approach is to first exhibit a query complexity ... more >>>


TR15-185 | 24th November 2015
Arnab Bhattacharyya, Sivakanth Gopi

Lower bounds for constant query affine-invariant LCCs and LTCs

Affine-invariant codes are codes whose coordinates form a vector space over a finite field and which are invariant under affine transformations of the coordinate space. They form a natural, well-studied class of codes; they include popular codes such as Reed-Muller and Reed-Solomon. A particularly appealing feature of affine-invariant codes is ... more >>>


TR13-100 | 15th July 2013
Hervé Fournier, Nutan Limaye, Guillaume Malod, Srikanth Srinivasan

Lower bounds for depth $4$ formulas computing iterated matrix multiplication

We study the arithmetic complexity of iterated matrix multiplication. We show that any multilinear homogeneous depth $4$ arithmetic formula computing the product of $d$ generic matrices of size $n \times n$, IMM$_{n,d}$, has size $n^{\Omega(\sqrt{d})}$ as long as $d \leq n^{1/10}$. This improves the result of Nisan and Wigderson (Computational ... more >>>


TR13-068 | 3rd May 2013
Mrinal Kumar, Shubhangi Saraf

Lower Bounds for Depth 4 Homogenous Circuits with Bounded Top Fanin

We study the class of homogenous $\Sigma\Pi\Sigma\Pi(r)$ circuits, which are depth 4 homogenous circuits with top fanin bounded by $r$. We show that any homogenous $\Sigma\Pi\Sigma\Pi(r)$ circuit computing the permanent of an $n\times n$ matrix must have size at least $\exp\left(n^{\Omega(1/r)}\right)$.

In a recent result, Gupta, Kamath, Kayal and ... more >>>


TR14-089 | 16th July 2014
Neeraj Kayal, Chandan Saha

Lower Bounds for Depth Three Arithmetic Circuits with small bottom fanin

Revisions: 1

Shpilka and Wigderson (CCC 1999) had posed the problem of proving exponential lower bounds for (nonhomogeneous) depth three arithmetic circuits with bounded bottom fanin over a field $\mathbb{F}$ of characteristic zero. We resolve this problem by proving a $N^{\Omega(\frac{d}{\tau})}$ lower bound for (nonhomogeneous) depth three arithmetic circuits with bottom fanin ... more >>>


TR10-120 | 27th July 2010
Noa Eidelstein, Alex Samorodnitsky

Lower bounds for designs in symmetric spaces

A design is a finite set of points in a space on which every "simple" functions averages to its global mean. Illustrative examples of simple functions are low-degree polynomials on the Euclidean sphere or on the Hamming cube.

We prove lower bounds on designs in spaces with a large group ... more >>>


TR13-116 | 29th August 2013
Albert Atserias, Moritz Müller, Sergi Oliva

Lower Bounds for DNF-Refutations of a Relativized Weak Pigeonhole Principle

The relativized weak pigeonhole principle states that if at least $2n$ out of $n^2$ pigeons fly into $n$ holes, then some hole must be doubly occupied. We prove that every DNF-refutation of the CNF encoding of this principle requires size $2^{(\log n)^{3/2-\epsilon}}$ for every $\epsilon > 0$ and every sufficiently ... more >>>


TR16-165 | 30th October 2016
Arkadev Chattopadhyay, Pavel Dvo?ák, Michal Koucky, Bruno Loff, Sagnik Mukhopadhyay

Lower Bounds for Elimination via Weak Regularity

We consider the problem of elimination in communication complexity, that was first raised by Ambainis et al. and later studied by Beimel et al. for its connection to the famous direct sum question. In this problem, let $f:\{0,1\}^n \to \{0,1\}$ be any boolean function. Alice and Bob get $k$ inputs ... more >>>


TR07-137 | 6th November 2007
Yijia Chen, Jörg Flum, Moritz Müller

Lower Bounds for Kernelizations

Among others, refining the methods of [Fortnow and Santhanam, ECCC Report TR07-096] we improve a result of this paper and show for any parameterized problem with a ``linear weak OR'' and with NP-hard underlying classical problem that there is no polynomial reduction from the problem to itself that assigns to ... more >>>


TR01-080 | 14th November 2001
Oded Goldreich, Howard Karloff, Leonard J. Schulman, Luca Trevisan

Lower Bounds for Linear Locally Decodable Codes and Private Information Retrieval

Revisions: 3


We prove that if a linear error correcting code
$\C:\{0,1\}^n\to\{0,1\}^m$ is such that a bit of the message can
be probabilistically reconstructed by looking at two entries of a
corrupted codeword, then $m = 2^{\Omega(n)}$. We also present
several extensions of this result.

We show a reduction from the ... more >>>


TR99-019 | 7th June 1999
Detlef Sieling

Lower Bounds for Linear Transformed OBDDs and FBDDs


Linear Transformed Ordered Binary Decision Diagrams (LTOBDDs) have
been suggested as a generalization of OBDDs for the representation and
manipulation of Boolean functions. Instead of variables as in the
case of OBDDs parities of variables may be tested at the nodes of an
LTOBDD. By this extension it is ... more >>>


TR03-057 | 21st July 2003
Scott Aaronson

Lower Bounds for Local Search by Quantum Arguments

The problem of finding a local minimum of a black-box function is central
for understanding local search as well as quantum adiabatic algorithms.
For functions on the Boolean hypercube {0,1}^n, we show a lower bound of
Omega(2^{n/4}/n) on the number of queries needed by a quantum computer to
solve this ... more >>>


TR05-053 | 4th May 2005
Paul Beame, Nathan Segerlind

Lower bounds for Lovasz-Schrijver systems and beyond follow from multiparty communication complexity

We prove that an \omega(log^3 n) lower bound for the three-party number-on-the-forehead (NOF) communication complexity of the set-disjointness function implies an n^\omega(1) size lower bound for tree-like Lovasz-Schrijver systems that refute unsatisfiable CNFs. More generally, we prove that an n^\Omega(1) lower bound for the (k+1)-party NOF communication complexity of set-disjointness ... more >>>


TR01-060 | 23rd August 2001
Amir Shpilka

Lower bounds for matrix product

We prove lower bounds on the number of product gates in bilinear
and quadratic circuits that
compute the product of two $n \times n$ matrices over finite fields.
In particular we obtain the following results:

1. We show that the number of product gates in any bilinear
(or quadratic) ... more >>>


TR00-029 | 30th April 2000
Ran Raz, Amir Shpilka

Lower Bounds for Matrix Product, in Bounded Depth Circuits with Arbitrary Gates

Revisions: 1

We prove super-linear lower bounds for the number of edges
in constant depth circuits with $n$ inputs and up to $n$ outputs.
Our lower bounds are proved for all types of constant depth
circuits, e.g., constant depth arithmetic circuits, constant depth
threshold circuits ... more >>>


TR14-169 | 9th December 2014
Stasys Jukna

Lower Bounds for Monotone Counting Circuits

A {+,x}-circuit counts a given multivariate polynomial f, if its values on 0-1 inputs are the same as those of f; on other inputs the circuit may output arbitrary values. Such a circuit counts the number of monomials of evaluated to 1 by a given 0-1 input vector (with multiplicities ... more >>>


TR97-032 | 11th July 1997
Jan Johannsen

Lower Bounds for Monotone Real Circuit Depth and Formula Size and Tree-like Cutting Planes

Using a notion of real communication complexity recently
introduced by J. Krajicek, we prove a lower bound on the depth of
monotone real circuits and the size of monotone real formulas for
st-connectivity. This implies a super-polynomial speed-up of dag-like
over tree-like Cutting Planes proofs.

more >>>

TR95-001 | 1st January 1995
Amos Beimel, Anna Gal, Michael S. Paterson

Lower Bounds for Monotone Span Programs

The model of span programs is a linear algebraic model of
computation. Lower bounds for span programs imply lower bounds for
contact schemes, symmetric branching programs and for formula size.
Monotone span programs correspond also to linear secret-sharing schemes.
We present a new technique for proving lower bounds for ... more >>>


TR07-014 | 23rd January 2007
Amit Chakrabarti

Lower Bounds for Multi-Player Pointer Jumping

We consider the $k$-layer pointer jumping problem in the one-way
multi-party number-on-the-forehead communication model. In this problem,
the input is a layered directed graph with each vertex having outdegree
$1$, shared amongst $k$ players: Player~$i$ knows all layers {\em
except} the $i$th. The players must communicate, in the order
$1,2,\ldots,k$, ... 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 >>>


TR04-083 | 8th September 2004
Boaz Barak, Yehuda Lindell, Salil Vadhan

Lower Bounds for Non-Black-Box Zero Knowledge

We show new lower bounds and impossibility results for general (possibly <i>non-black-box</i>) zero-knowledge proofs and arguments. Our main results are that, under reasonable complexity assumptions:
<ol>
<li> There does not exist a two-round zero-knowledge <i>proof</i> system with perfect completeness for an NP-complete language. The previous impossibility result for two-round zero ... more >>>


TR00-042 | 21st June 2000
Lars Engebretsen

Lower Bounds for non-Boolean Constraint Satisfaction

Revisions: 1

We show that the k-CSP problem over a finite Abelian group G
cannot be approximated within |G|^{k-O(sqrt{k})}-epsilon, for
any constant epsilon>0, unless P=NP. This lower bound matches
well with the best known upper bound, |G|^{k-1}, of Serna,
Trevisan and Xhafa. The proof uses a combination of PCP
techniques---most notably a ... more >>>


TR15-022 | 9th February 2015
Nutan Limaye, Guillaume Malod, Srikanth Srinivasan

Lower bounds for non-commutative skew circuits

Revisions: 1

Nisan (STOC 1991) exhibited a polynomial which is computable by linear sized non-commutative circuits but requires exponential sized non-commutative algebraic branching programs. Nisan's hard polynomial is in fact computable by linear sized skew circuits (skew circuits are circuits where every multiplication gate has the property that all but one of ... more >>>


TR01-020 | 20th February 2001
N. S. Narayanaswamy, C.E. Veni Madhavan

Lower Bounds for OBDDs and Nisan's pseudorandom generator


We present a new boolean function for which any Ordered Binary
Decision Diagram (OBDD) computing it has an exponential number
of nodes. This boolean function is obtained from Nisan's
pseudorandom generator to derandomize space bounded randomized
algorithms. Though the relation between hardness and randomness for
computational models is well ... more >>>


TR13-083 | 7th June 2013
Miklos Ajtai

Lower Bounds for RAMs and Quantifier Elimination

For each natural number $d$ we consider a finite structure ${\bf M}_{d}$ whose universe is the set of all $0,1$-sequence of length $n=2^{d}$, each representing a natural number in the set $\lbrace 0,1,...,2^{n}-1\rbrace$ in binary form. The operations included in the structure are the four constants $0,1,2^{n}-1,n$, multiplication and addition ... more >>>


TR15-073 | 25th April 2015
Neeraj Kayal, Chandan Saha

Lower Bounds for Sums of Products of Low arity Polynomials

We prove an exponential lower bound for expressing a polynomial as a sum of product of low arity polynomials. Specifically, we show that for the iterated matrix multiplication polynomial, $IMM_{d, n}$ (corresponding to the product of $d$ matrices of size $n \times n$ each), any expression of the form
more >>>


TR02-064 | 14th November 2002
Andrej Bogdanov, Luca Trevisan

Lower Bounds for Testing Bipartiteness in Dense Graphs

We consider the problem of testing bipartiteness in the adjacency
matrix model. The best known algorithm, due to Alon and Krivelevich,
distinguishes between bipartite graphs and graphs that are
$\epsilon$-far from bipartite using $O((1/\epsilon^2)polylog(1/epsilon)$
queries. We show that this is optimal for non-adaptive algorithms,
up to the ... more >>>


TR13-036 | 13th March 2013
Eric Blais, Sofya Raskhodnikova, Grigory Yaroslavtsev

Lower Bounds for Testing Properties of Functions on Hypergrid Domains

Revisions: 1

We introduce strong, and in many cases optimal, lower bounds for the number of queries required to nonadaptively test three fundamental properties of functions $ f : [n]^d \rightarrow \mathbb R$ on the hypergrid: monotonicity, convexity, and the Lipschitz property.
Our lower bounds also apply to the more restricted setting ... more >>>


TR09-066 | 13th August 2009
Arnab Bhattacharyya, Ning Xie

Lower Bounds for Testing Triangle-freeness in Boolean Functions

Let $f_{1},f_{2}, f_{3}:\mathbb{F}_{2}^{n} \to \{0,1\}$ be three Boolean functions.
We say a triple $(x,y,x+y)$ is a \emph{triangle} in the function-triple $(f_{1}, f_{2}, f_{3})$ if $f_{1}(x)=f_{2}(y)=f_{3}(x+y)=1$.
$(f_{1}, f_{2}, f_{3})$ is said to be \emph{triangle-free} if there is no triangle in the triple. The distance between a function-triple
and ... more >>>


TR14-150 | 10th November 2014
Justin Thaler

Lower Bounds for the Approximate Degree of Block-Composed Functions

Revisions: 3

We describe a new hardness amplification result for point-wise approximation of Boolean functions by low-degree polynomials. Specifically, for any function $f$ on $N$ bits, define $F(x_1, \dots, x_M) = \text{OMB}(f(x_1), \dots, f(x_M))$ to be the function on $M \cdot N$ bits obtained by block-composing $f$ with a specific DNF known ... more >>>


TR14-139 | 31st October 2014
Hong Van Le

Lower bounds for the circuit size of partially homogeneous polynomials

Revisions: 1

In this paper
we associate to each multivariate polynomial $f$ that is homogeneous relative to a subset of its variables a series of polynomial families $P_\lambda (f)$ of $m$-tuples of homogeneous polynomials of equal degree such that the circuit size of any member in $P_\lambda (f)$ is bounded from above ... more >>>


TR94-019 | 12th December 1994

Lower Bounds for the Computational Power of Networks of Spiking

We investigate the computational power of a formal model for networks of
spiking neurons. It is shown that simple operations on phase-differences
between spike-trains provide a very powerful computational tool that can
in principle be used to carry out highly complex computations on a small
network of spiking neurons. We ... more >>>


TR95-034 | 30th June 1995
Christoph Meinel, Stephan Waack

Lower Bounds for the Majority Communication Complexity of Various Graph Accessibility Problems

We investigate the probabilistic communication complexity
(more exactly, the majority communication complexity,)
of the graph accessibility problem GAP and
its counting versions MOD_k-GAP, k > 1.
Due to arguments concerning matrix variation ranks
and certain projection reductions, we prove
that, for any partition of the input variables,
more >>>


TR97-042 | 22nd September 1997
Russell Impagliazzo, Pavel Pudlak, Jiri Sgall

Lower Bounds for the Polynomial Calculus and the Groebner Basis Algorithm

Razborov~\cite{Razborov96} recently proved that polynomial
calculus proofs of the pigeonhole principle $PHP_n^m$ must have
degree at least $\ceiling{n/2}+1$ over any field. We present a
simplified proof of the same result. The main
idea of our proof is the same as in the original proof
of Razborov: we want to describe ... more >>>


TR03-068 | 30th July 2003
Matthias Homeister

Lower Bounds for the Sum of Graph--driven Read--Once Parity Branching Programs

We prove the first lower bound for restricted read-once parity branching
programs with unlimited parity nondeterminism where for each input the
variables may be tested according to several orderings.

Proving a superpolynomial lower bound for read-once parity branching
programs is still a challenging open problem. The following variant ... more >>>


TR14-080 | 11th June 2014
Stasys Jukna

Lower Bounds for Tropical Circuits and Dynamic Programs

Revisions: 1

Tropical circuits are circuits with Min and Plus, or Max and Plus operations as gates. Their importance stems from their intimate relation to dynamic programming algorithms. The power of tropical circuits lies somewhere between that of monotone boolean circuits and monotone arithmetic circuits. In this paper we present some lower ... more >>>


TR10-085 | 20th May 2010
Eli Ben-Sasson, Jan Johannsen

Lower bounds for width-restricted clause learning on small width formulas

It has been observed empirically that clause learning does not significantly improve the performance of a SAT solver when restricted
to learning clauses of small width only. This experience is supported by lower bound theorems. It is shown that lower bounds on the runtime of width-restricted clause learning follow from ... more >>>


TR16-050 | 31st March 2016
Roei Tell

Lower Bounds on Black-Box Reductions of Hitting to Density Estimation

Revisions: 1

We consider the following problem. A deterministic algorithm tries to find a string in an unknown set $S\subseteq\{0,1\}^n$ that is guaranteed to have large density (e.g., $|S|\ge2^{n-1}$). However, the only information that the algorithm can obtain about $S$ is estimates of the density of $S$ in adaptively chosen subsets of ... 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 >>>


TR12-108 | 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 >>>


TR00-002 | 23rd December 1999
Michael Schmitt

Lower Bounds on the Complexity of Approximating Continuous Functions by Sigmoidal Neural Networks

We calculate lower bounds on the size of sigmoidal neural networks
that approximate continuous functions. In particular, we show that
for the approximation of polynomials the network size has to grow
as $\Omega((\log k)^{1/4})$ where $k$ is the degree of the polynomials.
This bound is ... more >>>


TR04-120 | 22nd November 2004
Andris Ambainis, William Gasarch, Aravind Srinivasan, Andrey Utis

Lower bounds on the Deterministic and Quantum Communication Complexity of HAM_n^a

Alice and Bob want to know if two strings of length $n$ are
almost equal. That is, do they differ on at most $a$ bits?
Let $0\le a\le n-1$.
We show that any deterministic protocol, as well as any
error-free quantum protocol ($C^*$ version), for this problem
requires at ... more >>>


TR00-022 | 2nd May 2000
Rosario Gennaro, Luca Trevisan

Lower bounds on the efficiency of generic cryptographic constructions

We present lower bounds on the efficiency of
constructions for Pseudo-Random Generators (PRGs) and
Universal One-Way Hash Functions (UOWHFs) based on
black-box access to one-way permutations. Our lower bounds are tight as
they match the efficiency of known constructions.

A PRG (resp. UOWHF) construction based on black-box access is
a ... more >>>


TR11-016 | 7th February 2011
Sergei Artemenko, Ronen Shaltiel

Lower bounds on the query complexity of non-uniform and adaptive reductions showing hardness amplification

Revisions: 1

Hardness amplification results show that for every function $f$ there exists a function $Amp(f)$ such that the following holds: if every circuit of size $s$ computes $f$ correctly on at most a $1-\delta$ fraction of inputs, then every circuit of size $s'$ computes $Amp(f)$ correctly on at most a $1/2+\eps$ ... more >>>


TR09-010 | 29th January 2009
Nikos Leonardos, Michael Saks

Lower bounds on the randomized communication complexity of read-once functions

We prove lower bounds on the randomized two-party communication complexity of functions that arise from read-once boolean formulae.

A read-once boolean formula is a formula in propositional logic with the property that every variable appears exactly once. Such a formula can be represented by a tree, where the leaves correspond ... more >>>


TR98-015 | 16th January 1998
Valentin E. Brimkov, Stefan S. Dantchev

Lower Bounds, "Pseudopolynomial" and Approximation Algorithms for the Knapsack Problem with Real Coefficients

In this paper we study the Boolean Knapsack problem (KP$_{{\bf R}}$)
$a^Tx=1$, $x \in \{0,1\}^n$ with real coefficients, in the framework
of the Blum-Shub-Smale real number computational model \cite{BSS}.
We obtain a new lower bound
$\Omega \left( n\log n\right) \cdot f(1/a_{\min})$ for the time
complexity ... more >>>


TR15-133 | 12th August 2015
Olaf Beyersdorff, Ilario Bonacina, Leroy Chew

Lower bounds: from circuits to QBF proof systems

A general and long-standing belief in the proof complexity community asserts that there is a close connection between progress in lower bounds for Boolean circuits and progress in proof size lower bounds for strong propositional proof systems. Although there are famous examples where a transfer from ideas and techniques from ... more >>>




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