English

On Hamilton cycles in Erd\H{o}s-R\'{e}nyi subgraphs of large graphs

Combinatorics 2018-11-09 v1

Abstract

Given a graph Γ=(V,E)\Gamma = (V, E) on nn vertices and mm edges, we define the Erd\H{o}s-R\'{e}nyi graph process with host Γ\Gamma as follows. A permutation e1,,eme_1,\dots,e_m of EE is chosen uniformly at random, and for tmt\leq m we let Γt=(V,{e1,,et})\Gamma_t = (V, \{e_1,\dots,e_t\}). Suppose the minimum degree of Γ\Gamma is δ(Γ)(1/2+ε)n\delta(\Gamma) \geq (1/2 + \varepsilon)n for some constant ε>0\varepsilon > 0. Then with high probability, Γt\Gamma_t becomes Hamiltonian at the same moment that its minimum degree becomes at least two. Given 0p10\leq p\leq 1 we let Γp\Gamma_p be the Erd\H{o}s-R\'{e}nyi subgraph of Γ\Gamma, obtained by retaining each edge independently with probability pp. When δ(Γ)(1/2+ε)n\delta(\Gamma)\geq (1/2 + \varepsilon)n, we provide a threshold function p0p_0 for Hamiltonicity, such that if (pp0)n(p-p_0)n\to -\infty then Γp\Gamma_p is not Hamiltonian whp, and if (pp0)n(p-p_0)n\to\infty then Γp\Gamma_p is Hamiltonian whp.

Keywords

Cite

@article{arxiv.1811.03501,
  title  = {On Hamilton cycles in Erd\H{o}s-R\'{e}nyi subgraphs of large graphs},
  author = {Tony Johansson},
  journal= {arXiv preprint arXiv:1811.03501},
  year   = {2018}
}