English

Long cycles in subgraphs of (pseudo)random directed graphs

Combinatorics 2010-09-21 v1

Abstract

We study the resilience of random and pseudorandom directed graphs with respect to the property of having long directed cycles. For every 0<γ<1/20 < \gamma < 1/2 we find a constant c=c(γ)c=c(\gamma) such that the following holds. Let G=(V,E)G=(V,E) be a (pseudo)random directed graph on nn vertices, and let GG' be a subgraph of GG with (1/2+γ)E(1/2+\gamma)|E| edges. Then GG' contains a directed cycle of length at least (co(1))n(c-o(1))n. Moreover, there is a subgraph GG'' of GG with (1/2+γo(1))E(1/2+\gamma-o(1))|E| edges that does not contain a cycle of length at least cncn.

Keywords

Cite

@article{arxiv.1009.3721,
  title  = {Long cycles in subgraphs of (pseudo)random directed graphs},
  author = {Ido Ben-Eliezer and Michael Krivelevich and Benny Sudakov},
  journal= {arXiv preprint arXiv:1009.3721},
  year   = {2010}
}