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Electronic Colloquium on Computational Complexity

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All reports by Author Igor Shinkar:

TR20-144 | 7th September 2020
Mohammad Jahanara, Sajin Koroth, Igor Shinkar

Toward Probabilistic Checking against Non-Signaling Strategies with Constant Locality

Non-signaling strategies are a generalization of quantum strategies that have been studied in physics over the past three decades. Recently, they have found applications in theoretical computer science, including to proving inapproximability results for linear programming and to constructing protocols for delegating computation. A central tool for these applications is ... more >>>

TR20-142 | 15th September 2020
Vahid Reza Asadi, Igor Shinkar

Relaxed Locally Correctable Codes with Improved Parameters

Locally decodable codes (LDCs) are error-correcting codes $C : \Sigma^k \to \Sigma^n$ that admit a local decoding algorithm that recovers each individual bit of the message by querying only a few bits from a noisy codeword. An important question in this line of research is to understand the optimal trade-off ... more >>>

TR20-113 | 27th July 2020
Alessandro Chiesa, Tom Gur, Igor Shinkar

Relaxed Locally Correctable Codes with Nearly-Linear Block Length and Constant Query Complexity

Locally correctable codes (LCCs) are error correcting codes C : \Sigma^k \to \Sigma^n which admit local algorithms that correct any individual symbol of a corrupted codeword via a minuscule number of queries. This notion is stronger than that of locally decodable codes (LDCs), where the goal is to only recover ... more >>>

TR19-070 | 14th May 2019
Alessandro Chiesa, Peter Manohar, Igor Shinkar

On Local Testability in the Non-Signaling Setting

Revisions: 1

Non-signaling strategies are a generalization of quantum strategies that have been studied in physics for decades, and have recently found applications in theoretical computer science. These applications motivate the study of local-to-global phenomena for non-signaling functions.

We present general results about the local testability of linear codes in the non-signaling ... more >>>

TR16-126 | 8th August 2016
Subhash Khot, Igor Shinkar

An $\widetilde{O}(n)$ Queries Adaptive Tester for Unateness

We present an adaptive tester for the unateness property of Boolean functions. Given a function $f:\{0,1\}^n \to \{0,1\}$ the tester makes $O(n \log(n)/\epsilon)$ adaptive queries to the function. The tester always accepts a unate function, and rejects with probability at least 0.9 any function that is $\epsilon$-far from being unate.
more >>>

TR15-132 | 13th August 2015
Daniel Reichman, Igor Shinkar

On Percolation and NP-Hardness

Revisions: 2

We consider the robustness of computational hardness of problems
whose input is obtained by applying independent random deletions to worst-case instances.
For some classical NP-hard problems on graphs, such as Coloring, Vertex-Cover, and Hamiltonicity, we examine the complexity of these problems when edges (or vertices) of an arbitrary
graph are ... more >>>

TR15-013 | 28th January 2015
Subhash Khot, Igor Shinkar

On Hardness of Approximating the Parameterized Clique Problem

In the $Gap-clique(k, \frac{k}{2})$ problem, the input is an $n$-vertex graph $G$, and the goal is to decide whether $G$ contains a clique of size $k$ or contains no clique of size $\frac{k}{2}$. It is an open question in the study of fixed parameterized tractability whether the $Gap-clique(k, \frac{k}{2})$ problem ... more >>>

TR14-160 | 27th November 2014
Gil Cohen, Igor Shinkar

Zero-Fixing Extractors for Sub-Logarithmic Entropy

An $(n,k)$-bit-fixing source is a distribution on $n$ bit strings, that is fixed on $n-k$ of the coordinates, and jointly uniform on the remaining $k$ bits. Explicit constructions of bit-fixing extractors by Gabizon, Raz and Shaltiel [SICOMP 2006] and Rao [CCC 2009], extract $(1-o(1)) \cdot k$ bits for $k = ... more >>>

TR14-099 | 7th August 2014
Gil Cohen, Igor Shinkar

The Complexity of DNF of Parities

We study depth 3 circuits of the form $\mathrm{OR} \circ \mathrm{AND} \circ \mathrm{XOR}$, or equivalently -- DNF of parities. This model was first explicitly studied by Jukna (CPC'06) who obtained a $2^{\Omega(n)}$ lower bound for explicit functions. Several related models have gained attention in the last few years, such as ... more >>>

TR14-002 | 8th January 2014
Roee David, Irit Dinur, Elazar Goldenberg, Guy Kindler, Igor Shinkar

Direct Sum Testing

Revisions: 1

For a string $a \in \{0,1\}^n$ its $k$-fold direct sum encoding is a function $f_a$ that takes as input sets $S \subseteq [n]$ of
size $k$ and outputs $f_a(S) = \sum_{i \in S} a_i$.
In this paper we are interested in the Direct Sum Testing Problem,
where we are given ... more >>>

TR13-148 | 26th October 2013
Irit Dinur, Igor Shinkar

On the Conditional Hardness of Coloring a 4-colorable Graph with Super-Constant Number of Colors

For $3 \leq q < Q$ we consider the $\text{ApproxColoring}(q,Q)$ problem of deciding for a given graph $G$ whether $\chi(G) \leq q$ or $\chi(G) \geq Q$. It was show in [DMR06] that the problem $\text{ApproxColoring}(q,Q)$ is NP-hard for $q=3,4$ and arbitrary large constant $Q$ under variants of the Unique Games ... more >>>

TR13-138 | 5th October 2013
Itai Benjamini, Gil Cohen, Igor Shinkar

Bi-Lipschitz Bijection between the Boolean Cube and the Hamming Ball

Revisions: 1

We construct a bi-Lipschitz bijection from the Boolean cube to the Hamming ball of equal volume. More precisely, we show that for all even $n \in {\mathbb N}$ there exists an explicit bijection $\psi \colon \{0,1\}^n \to \left\{ x \in \{0,1\}^{n+1} \colon |x| > n/2 \right\}$ such that for every ... more >>>

TR12-095 | 23rd July 2012
Avraham Ben-Aroya, Igor Shinkar

A Note on Subspace Evasive Sets

A subspace-evasive set over a field ${\mathbb F}$ is a subset of ${\mathbb F}^n$ that has small intersection with any low-dimensional affine subspace of ${\mathbb F}^n$. Interest in subspace evasive sets began in the work of Pudlák and Rödl (Quaderni di Matematica 2004). More recently, Guruswami (CCC 2011) showed that ... more >>>

TR12-021 | 14th March 2012
Oded Goldreich, Igor Shinkar

Two-Sided Error Proximity Oblivious Testing

Revisions: 4

Loosely speaking, a proximity-oblivious (property) tester is a randomized algorithm that makes a constant number of queries to a tested object and distinguishes objects that have a predetermined property from those that lack it. Specifically, for some threshold probability $c$, objects having the property are accepted with probability at least ... more >>>

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