Information Security and Cryptography Research Group

Parallel Repetition: Simplifications and the No-Signaling Case

Thomas Holenstein

Proc. 39th ACM Symposium on Theory of Computing — STOC 2007, pp. 411–419, Jun 2007.

In a two-player refereed game, a referee chooses (x,y) according to a publicly known distribution P_XY, sends x to Alice, and y to Bob. Without communicating with each other, Alice responds with a value ä" and Bob responds with a value "b". Alice and Bob jointly win if a publicly known predicate Q(x,y,a,b) holds. Let such a game be given and assume that the maximum probability that Alice and Bob can win is v<1. Raz (SIAM J. Comput. 27, 1998) shows that if the game is repeated n times in parallel, then the probability that Alice and Bob win all games simultaneously is at most v'^(n/log(s)), where s is the maximal number of possible responses from Alice and Bob in the initial game, and v' is a constant depending only on v. In this work, we simplify Raz's proof in various ways and thus shorten it significantly. Further we study the case where Alice and Bob are not restricted to local computations and can use any strategy which does not imply communication among them.

BibTeX Citation

@inproceedings{Holens07,
author       = {Thomas Holenstein},
title        = {Parallel Repetition: Simplifications and the No-Signaling Case},
editor       = {David S. Johnson and Uriel Feige},
booktitle    = {Proc.~39th ACM Symposium on Theory of Computing --- STOC 2007},
pages        = 411--419,
year         = 2007,
month        = 6,
}