English

The hypergraph removal process

Combinatorics 2025-08-05 v2 Probability

Abstract

Let k2k\geq 2 and fix a kk-uniform hypergraph F\mathcal{F}. Consider the random process that, starting from a kk-uniform hypergraph H\mathcal{H} on nn vertices, repeatedly deletes the edges of a copy of F\mathcal{F} chosen uniformly at random and terminates when no copies of F\mathcal{F} remain. Let R(H,F)R(\mathcal{H},\mathcal{F}) denote the number of edges that are left after termination. We show that R(H,F)=nk1/ρ±o(1)R(\mathcal{H},\mathcal{F})=n^{k-1/\rho\pm o(1)}, where ρ:=(E(F)1)/(V(F)k)\rho:=(\lvert E(\mathcal{F})\rvert-1)/(\lvert V(\mathcal{F})\rvert -k), holds with high probability provided that F\mathcal{F} is strictly kk-balanced and H\mathcal{H} is sufficiently dense with pseudorandom properties. Since we may in particular choose F\mathcal{F} and H\mathcal{H} to be complete graphs, this confirms the major folklore conjecture in the area in a very strong form.

Keywords

Cite

@article{arxiv.2412.15039,
  title  = {The hypergraph removal process},
  author = {Felix Joos and Marcus Kühn},
  journal= {arXiv preprint arXiv:2412.15039},
  year   = {2025}
}

Comments

66 pages + 21 pages appendix; typos corrected