English

Clique factors in randomly perturbed graphs: the transition points

Combinatorics 2024-11-20 v2

Abstract

A randomly perturbed graph Gp=GαG(n,p)G^p = G_\alpha \cup G(n,p) is obtained by taking a deterministic nn-vertex graph Gα=(V,E)G_\alpha = (V, E) with minimum degree δ(G)αn\delta(G)\geq \alpha n and adding the edges of the binomial random graph G(n,p)G(n,p) defined on the same vertex set VV. For which value pp (depending on α\alpha) does the graph GpG^p contain a KrK_r-factor (a spanning collection of vertex-disjoint KrK_r-copies) with high probability? The order of magnitude of the minimal value of pp has been determined whenever α1sr\alpha \neq 1- \frac{s}{r} for an integer ss (see Han, Morris, and Treglown [RSA, 2021] and Balogh, Treglown, and Wagner [CPC, 2019]). We establish the minimal probability psp_s (up to a constant factor) for all values of α=1sr12\alpha = 1-\frac{s}{r} \leq \frac 12, and show that the threshold exhibits a polynomial jump at α=1sr\alpha = 1-\frac{s}{r} compared to the surrounding intervals. An extremal example GαG_{\alpha} which shows that psp_s is optimal up to a constant factor differs from the previous (usually multipartite) examples in containing a pseudorandom induced subgraph.

Keywords

Cite

@article{arxiv.2410.11003,
  title  = {Clique factors in randomly perturbed graphs: the transition points},
  author = {Sylwia Antoniuk and Nina Kamčev and Christian Reiher},
  journal= {arXiv preprint arXiv:2410.11003},
  year   = {2024}
}
R2 v1 2026-06-28T19:21:31.411Z