Average-Case Hardness of Binary-Encoded Clique in Proof and Communication Complexity

2026-05-11Computational Complexity

Computational Complexity
AI summary

The authors investigate how hard it is on average to prove that a random dense graph does not contain a large clique, focusing on certain mathematical proof methods and communication tasks. They prove that some common proof techniques require exponentially long explanations to show no large clique exists in these graphs. However, they also find that if two parties try to find an error in these proofs using randomized communication, it can be done with only polynomial effort. This work gives insights into the complexity of reasoning about cliques in random graphs.

average-case hardnesscliqueproof complexitycommunication complexitycutting planesresolution over paritiesrandomized communication complexityrandom graphsfalsified clausebinary encoding
Authors
Susanna F. de Rezende, David Engström, Yassine Ghannane, Duri Andrea Janett, Artur Riazanov
Abstract
We study the average-case hardness of establishing that a graph does not have a large clique in both proof and communication complexity. We show exponential lower bounds on the length of cutting planes and bounded-depth resolution over parities refutations of the binary encoding of clique formulas on randomly sampled dense graphs. Moreover, we show that the randomized communication complexity of finding a falsified clause in these formulas is polynomial.