Oded Goldreich

We consider the problem of estimating the average of a huge set of values.

That is,

given oracle access to an arbitrary function $f:\{0,1\}^n\mapsto[0,1]$,

we need to estimate $2^{-n} \sum_{x\in\{0,1\}^n} f(x)$

upto an additive error of $\epsilon$.

We are allowed to employ a randomized algorithm which may ...
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Oded Goldreich

Contemplating the recently announced 1-local expanders of Viola and Wigderson (ECCC, TR16-129, 2016), one may observe that weaker constructs are well know. For example, one may easily obtain a 4-regular $N$-vertex graph with spectral gap that is $\Omega(1/\log^2 N)$, and similarly a $O(1)$-regular $N$-vertex graph with spectral gap $1/\tildeO(\log N)$.

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Itai Benjamini, Oded Goldreich

We introduce the notion of pseudo-mixing time of a graph define as the number of steps in a random walk that suffices for generating a vertex that looks random to any polynomial-time observer, where, in addition to the tested vertex, the observer is also provided with oracle access to the ... more >>>

Gil Cohen, Noam Peri, Amnon Ta-Shma

In this work we ask the following basic question: assume the vertices of an expander graph are labelled by $0,1$. What "test" functions $f : \{ 0,1\}^t \to \{0,1\}$ cannot distinguish $t$ independent samples from those obtained by a random walk? The expander hitting property due to Ajtai, Komlos and ... more >>>