English

The optimal edge-colouring threshold

Combinatorics 2022-12-09 v1

Abstract

Consider any dense r-regular quasirandom bipartite graph H with parts of size n and fix a set of r colours. Let L be a random list assignment where each colour is available for each edge of H with probability p. We show that the threshold probability for H to have a proper L-edge-colouring is p of order (log n)/n. This answers a question of Kang, Kelly, K\"uhn, Methuku and Osthus. We thus obtain the same threshold for Steiner Triple Systems and Latin squares; the latter answers a question of Johanssen from 2006.

Keywords

Cite

@article{arxiv.2212.04397,
  title  = {The optimal edge-colouring threshold},
  author = {Peter Keevash},
  journal= {arXiv preprint arXiv:2212.04397},
  year   = {2022}
}

Comments

21 pages

R2 v1 2026-06-28T07:26:23.544Z