English

Perfect Matching in Random Graphs is as Hard as Tseitin

Computational Complexity 2023-06-22 v3

Abstract

We study the complexity of proving that a sparse random regular graph on an odd number of vertices does not have a perfect matching, and related problems involving each vertex being matched some pre-specified number of times. We show that this requires proofs of degree Ω(n/logn)\Omega(n / \log n) in the Polynomial Calculus (over fields of characteristic 2\ne 2) and Sum-of-Squares proof systems, and exponential size in the bounded-depth Frege proof system. This resolves a question by Razborov asking whether the Lov\'asz-Schrijver proof system requires nδn^\delta rounds to refute these formulas for some δ>0\delta > 0. The results are obtained by a worst-case to average-case reduction of these formulas relying on a topological embedding theorem which may be of independent interest.

Keywords

Cite

@article{arxiv.2201.10835,
  title  = {Perfect Matching in Random Graphs is as Hard as Tseitin},
  author = {Per Austrin and Kilian Risse},
  journal= {arXiv preprint arXiv:2201.10835},
  year   = {2023}
}

Comments

43 pages, 4 figures, SODA 2022

R2 v1 2026-06-24T09:03:22.995Z