English

Counting Perfect Matchings in Dense Graphs Is Hard

Data Structures and Algorithms 2022-10-28 v1 Combinatorics

Abstract

We show that the problem of counting perfect matchings remains #P-complete even if we restrict the input to very dense graphs, proving the conjecture in [5]. Here "dense graphs" refer to bipartite graphs of bipartite independence number 2\leq 2, or general graphs of independence number 2\leq 2. Our proof is by reduction from counting perfect matchings in bipartite graphs, via elementary linear algebra tricks and graph constructions.

Keywords

Cite

@article{arxiv.2210.15014,
  title  = {Counting Perfect Matchings in Dense Graphs Is Hard},
  author = {Nicolas El Maalouly and Yanheng Wang},
  journal= {arXiv preprint arXiv:2210.15014},
  year   = {2022}
}
R2 v1 2026-06-28T04:36:00.429Z