# A New Proof of Nonsignalling Multiprover Parallel Repetition Theorem

## TL;DR

This paper provides a new information-theoretic proof of the nonsignalling multiprover parallel repetition theorem, enhancing understanding of hardness of approximation in computational complexity.

## Contribution

It introduces a novel proof technique based on a recent method for strong converse results, replacing de Finetti decompositions with a change of measure approach.

## Key findings

- New proof simplifies understanding of the theorem
- Extends techniques from multiuser information theory
- Potentially impacts hardness of approximation results

## Abstract

We present an information theoretic proof of the nonsignalling multiprover parallel repetition theorem, a recent extension of its two-prover variant that underlies many hardness of approximation results. The original proofs used de Finetti type decomposition for strategies. We present a new proof that is based on a technique we introduced recently for proving strong converse results in multiuser information theory and entails a change of measure after replacing hard information constraints with soft ones.