A natural measure of smoothness of a Boolean function is its sensitivity (the largest number of Hamming neighbors of a point which differ from it in function value). The structure of smooth or equivalently low-sensitivity functions is still a mystery. A well-known conjecture states that every such Boolean function can ... more >>>

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 >>>

We present a very simple reduction that when given a graph G and an integer k produces a game that has an evolutionary stable strategy if and only if the maximum clique size of G is not exactly k. Formally this shows that existence of evolutionary stable strategies is hard ... more >>>

We consider computationally-efficient incentive-compatible
mechanisms that use the VCG payment scheme, and study how well they
can approximate the social welfare in auction settings. We obtain a
$2$-approximation for multi-unit auctions, and show that this is
best possible, even though from a purely computational perspective
an FPTAS exists. For combinatorial ... more >>>

We consider the well known problem of determining the k'th
vertex reached by chasing pointers in a directed graph of
out-degree 1. The famous "pointer doubling" technique
provides an O(log k) parallel time algorithm on a
Concurrent-Read Exclusive-Write (CREW) PRAM. We prove that ... more >>>

We show how to construct length-preserving 1-1 one-way
functions based on popular intractability assumptions (e.g., RSA, DLP).
Such 1-1 functions should not
be confused with (infinite) families of (finite) one-way permutations.
What we want and obtain is a single (infinite) 1-1 one-way function.

We present a Logspace, many-one reduction from the undirected
st-connectivity problem to its complement. This shows that
$SL=co-SL$

This paper concerns the open problem of Lovasz and
Saks regarding the relationship between the communication complexity
of a boolean function and the rank of the associated matrix.
We first give an example exhibiting the largest gap known. We then
prove two related theorems.