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Electronic Colloquium on Computational Complexity

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All reports by Author Omri Weinstein:

TR17-047 | 10th March 2017
Kasper Green Larsen, Omri Weinstein, Huacheng Yu

Crossing the Logarithmic Barrier for Dynamic Boolean Data Structure Lower Bounds

This paper proves the first super-logarithmic lower bounds on the cell probe complexity of dynamic \emph{boolean} (a.k.a. decision) data structure problems, a long-standing milestone in data structure lower bounds.

We introduce a new method for proving dynamic cell probe lower bounds and use it to prove a $\tilde{\Omega}(\log^{1.5} ... more >>>

TR16-110 | 19th July 2016
Alexander Golovnev, Oded Regev, Omri Weinstein

The Minrank of Random Graphs

Revisions: 1

The minrank of a graph $G$ is the minimum rank of a matrix $M$ that can be obtained from the adjacency matrix of $G$ by switching ones to zeros (i.e., deleting edges) and setting all diagonal entries to one. This quantity is closely related to the fundamental information-theoretic problems of ... more >>>

TR16-055 | 11th April 2016
Tim Roughgarden, Omri Weinstein

On the Communication Complexity of Approximate Fixed Points

We study the two-party communication complexity of finding an approximate Brouwer fixed point of a composition
of two Lipschitz functions $g\circ f : [0,1]^n \to [0,1]^n$, where Alice holds $f$ and Bob holds $g$. We prove an
exponential (in $n$) lower bound on the deterministic ... more >>>

TR16-054 | 11th April 2016
Omri Weinstein, Huacheng Yu

Amortized Dynamic Cell-Probe Lower Bounds from Four-Party Communication

This paper develops a new technique for proving amortized, randomized cell-probe lower bounds on dynamic
data structure problems. We introduce a new randomized nondeterministic four-party communication model
that enables "accelerated", error-preserving simulations of dynamic data structures.

We use this technique to prove an $\Omega(n\left(\log n/\log\log n\right)^2)$ cell-probe ... more >>>

TR15-084 | 21st May 2015
Or Ordentlich, Ofer Shayevitz, Omri Weinstein

Dictatorship is the Most Informative Balanced Function at the Extremes

Revisions: 2

Suppose $X$ is a uniformly distributed $n$-dimensional binary vector and $Y$ is obtained by passing $X$ through a binary symmetric channel with crossover probability $\alpha$. A recent conjecture by Courtade and Kumar postulates that $I(f(X);Y)\leq 1-h(\alpha)$ for any Boolean function $f$. In this paper, we prove the conjecture for all ... more >>>

TR15-083 | 14th May 2015
Omri Weinstein, David Woodruff

The Simultaneous Communication of Disjointness with Applications to Data Streams

We study $k$-party set disjointness in the simultaneous message-passing model, and show that even if each element $i\in[n]$ is guaranteed to either belong to all $k$ parties or to at most $O(1)$ parties in expectation (and to at most $O(\log n)$ parties with high probability), then $\Omega(n \min(\log 1/\delta, \log ... more >>>

TR15-074 | 29th April 2015
Mark Braverman, Young Kun Ko, Aviad Rubinstein, Omri Weinstein

ETH Hardness for Densest-$k$-Subgraph with Perfect Completeness

We show that, assuming the (deterministic) Exponential Time Hypothesis, distinguishing between a graph with an induced $k$-clique and a graph in which all $k$-subgraphs have density at most $1-\epsilon$, requires $n^{\tilde \Omega(log n)}$ time. Our result essentially matches the quasi-polynomial algorithms of Feige and Seltser [FS97] and Barman [Bar15] for ... more >>>

TR15-060 | 14th April 2015
Omri Weinstein

Information Complexity and the Quest for Interactive Compression

Revisions: 1

Information complexity is the interactive analogue of Shannon's classical information theory. In recent years this field has emerged as a powerful tool for proving strong communication lower bounds, and for addressing some of the major open problems in communication complexity and circuit complexity. A notable achievement of information complexity is ... more >>>

TR15-054 | 7th April 2015
Noga Alon, Noam Nisan, Ran Raz, Omri Weinstein

Welfare Maximization with Limited Interaction

We continue the study of welfare maximization in unit-demand (matching) markets, in a distributed information model
where agent's valuations are unknown to the central planner, and therefore communication is required to determine an
efficient allocation. Dobzinski, Nisan and Oren (STOC'14) showed that if the market size is $n$, ... more >>>

TR14-092 | 22nd July 2014
Mark Braverman, Young Kun Ko, Omri Weinstein

Approximating the best Nash Equilibrium in $n^{o(\log n)}$-time breaks the Exponential Time Hypothesis

The celebrated PPAD hardness result for finding an exact Nash equilibrium in a two-player game
initiated a quest for finding \emph{approximate} Nash equilibria efficiently, and is one of the major open questions in algorithmic game theory.

We study the computational complexity of finding an $\eps$-approximate Nash equilibrium with good social ... more >>>

TR14-047 | 8th April 2014
Mark Braverman, Omri Weinstein

An Interactive Information Odometer with Applications

Revisions: 1

We introduce a novel technique which enables two players to maintain an estimate of the internal information cost of their conversation in an online fashion without revealing much extra information. We use this construction to obtain new results about communication complexity and information-theoretically secure computation.

As a first corollary, ... more >>>

TR13-190 | 28th December 2013
Dmitry Gavinsky, Or Meir, Omri Weinstein, Avi Wigderson

Toward Better Formula Lower Bounds: An Information Complexity Approach to the KRW Composition Conjecture

Revisions: 10

One of the major open problems in complexity theory is proving super-polynomial lower bounds for circuits with logarithmic depth (i.e., $\mathbf{P}\not\subseteq\mathbf{NC}_1~$). This problem is interesting for two reasons: first, it is tightly related to understanding the power of parallel computation and of small-space computation; second, it is one of the ... more >>>

TR13-035 | 6th March 2013
Mark Braverman, Anup Rao, Omri Weinstein, Amir Yehudayoff

Direct product via round-preserving compression

Revisions: 1

We obtain a strong direct product theorem for two-party bounded round communication complexity.
Let suc_r(\mu,f,C) denote the maximum success probability of an r-round communication protocol that uses
at most C bits of communication in computing f(x,y) when (x,y)~\mu.
Jain et al. [JPY12] have recently showed that if
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 >>>

TR12-171 | 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 >>>

TR12-143 | 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 >>>

TR11-164 | 9th December 2011
Mark Braverman, Omri Weinstein

A discrepancy lower bound for information complexity

This paper provides the first general technique for proving information lower bounds on two-party
unbounded-rounds communication problems. We show that the discrepancy lower bound, which
applies to randomized communication complexity, also applies to information complexity. More
precisely, if the discrepancy of a two-party function $f$ with respect ... more >>>

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