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REPORTS > KEYWORD > HIGH DIMENSIONAL EXPANDERS:
Reports tagged with high dimensional expanders:
TR18-075 | 23rd April 2018
Irit Dinur, Yotam Dikstein, Yuval Filmus, Prahladh Harsha

#### Boolean function analysis on high-dimensional expanders

Revisions: 3

We initiate the study of Boolean function analysis on high-dimensional expanders. We describe an analog of the Fourier expansion and of the Fourier levels on simplicial complexes, and generalize the FKN theorem to high-dimensional expanders.

Our results demonstrate that a high-dimensional expanding complex X can sometimes serve as a sparse ... more >>>

TR18-134 | 24th July 2018
Tali Kaufman, David Mass

#### Cosystolic Expanders over any Abelian Group

In this work we show a general reduction from high dimensional complexes to their links based on the spectral properties of the links. We use this reduction to show that if a certain property is testable in the links, then it is also testable in the complex. In particular, we ... more >>>

TR19-112 | 1st September 2019
Yotam Dikstein, Irit Dinur

#### Agreement testing theorems on layered set systems

We introduce a framework of layered subsets, and give a sufficient condition for when a set system supports an agreement test. Agreement testing is a certain type of property testing that generalizes PCP tests such as the plane vs. plane test.

Previous work has shown that high dimensional expansion ... more >>>

TR19-124 | 28th August 2019
Roy Gotlib, Tali Kaufman

#### Testing Odd Direct Sums Using High Dimensional Expanders

In this work, using methods from high dimensional expansion, we show that the property of $k$-direct-sum is testable for odd values of $k$ . Previous work of Kaufman and Lubotzky could inherently deal only with the case that $k$ is even, using a reduction to linearity testing.
Interestingly, our work ... more >>>

TR19-126 | 19th September 2019
Irit Dinur, Roy Meshulam

#### Near Coverings and Cosystolic Expansion -- an example of topological property testing

We study the stability of covers of simplicial complexes. Given a map f:Y?X that satisfies almost all of the local conditions of being a cover, is it close to being a genuine cover of X? Complexes X for which this holds are called cover-stable. We show that this is equivalent ... more >>>

TR20-072 | 5th May 2020
Yotam Dikstein, Irit Dinur, Prahladh Harsha, Noga Ron-Zewi

#### Locally testable codes via high-dimensional expanders

Locally testable codes (LTC) are error-correcting codes that have a local tester which can distinguish valid codewords from words that are far from all codewords, by probing a given word only at a very small (sublinear, typically constant) number of locations. Such codes form the combinatorial backbone of PCPs. ... more >>>

TR20-136 | 11th September 2020
Irit Dinur, Yuval Filmus, Prahladh Harsha, Madhur Tulsiani

#### Explicit and structured sum of squares lower bounds from high dimensional expanders

We construct an explicit family of 3XOR instances which is hard for Omega(sqrt(log n)) levels of the Sum-of-Squares hierarchy. In contrast to earlier constructions, which involve a random component, our systems can be constructed explicitly in deterministic polynomial time.
Our construction is based on the high-dimensional expanders devised by Lubotzky, ... more >>>

TR20-170 | 9th November 2020
Max Hopkins, Tali Kaufman, Shachar Lovett

#### High Dimensional Expanders: Random Walks, Pseudorandomness, and Unique Games

Revisions: 1

Higher order random walks (HD-walks) on high dimensional expanders have played a crucial role in a number of recent breakthroughs in theoretical computer science, perhaps most famously in the recent resolution of the Mihail-Vazirani conjecture (Anari et al. STOC 2019), which focuses on HD-walks on one-sided local-spectral expanders. In this ... more >>>

TR21-168 | 17th November 2021
Tom Gur, Noam Lifshitz, Siqi Liu

#### Hypercontractivity on High Dimensional Expanders: Approximate Efron-Stein Decompositions for $\epsilon$-Product Spaces

Revisions: 2

We prove hypercontractive inequalities on high dimensional expanders. As in the settings of the p-biased hypercube, the symmetric group, and the Grassmann scheme, our inequalities are effective for global functions, which are functions that are not significantly affected by a restriction of a small set of coordinates. As applications, we ... more >>>

TR21-169 | 24th November 2021
Mitali Bafna, Max Hopkins, Tali Kaufman, Shachar Lovett

#### Hypercontractivity on High Dimensional Expanders: a Local-to-Global Approach for Higher Moments

Hypercontractivity is one of the most powerful tools in Boolean function analysis. Originally studied over the discrete hypercube, recent years have seen increasing interest in extensions to settings like the $p$-biased cube, slice, or Grassmannian, where variants of hypercontractivity have found a number of breakthrough applications including the resolution of ... more >>>

TR22-077 | 13th May 2022
Max Hopkins, Ting-Chun Lin

#### Explicit Lower Bounds Against $\Omega(n)$-Rounds of Sum-of-Squares

We construct an explicit family of 3-XOR instances hard for $\Omega(n)$-levels of the Sum-of-Squares (SoS) semi-definite programming hierarchy. Not only is this the first explicit construction to beat brute force search (beyond low-order improvements (Tulsiani 2021, Pratt 2021)), combined with standard gap amplification techniques it also matches the (optimal) hardness ... more >>>

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