Resilient degree sequences with respect to Hamilton cycles and matchings in random graphs
Abstract
P\'osa's theorem states that any graph whose degree sequence satisfies for all has a Hamilton cycle. This degree condition is best possible. We show that a similar result holds for suitable subgraphs of random graphs, i.e. we prove a `resilience version' of P\'osa's theorem: if and the -th vertex degree (ordered increasingly) of is at least for all , then has a Hamilton cycle. This is essentially best possible and strengthens a resilience version of Dirac's theorem obtained by Lee and Sudakov. Chv\'atal's theorem generalises P\'osa's theorem and characterises all degree sequences which ensure the existence of a Hamilton cycle. We show that a natural guess for a resilience version of Chv\'atal's theorem fails to be true. We formulate a conjecture which would repair this guess, and show that the corresponding degree conditions ensure the existence of a perfect matching in any subgraph of which satisfies these conditions. This provides an asymptotic characterisation of all degree sequences which resiliently guarantee the existence of a perfect matching.
Keywords
Cite
@article{arxiv.1810.12433,
title = {Resilient degree sequences with respect to Hamilton cycles and matchings in random graphs},
author = {Padraig Condon and Alberto Espuny Díaz and Jaehoon Kim and Daniela Kühn and Deryk Osthus},
journal= {arXiv preprint arXiv:1810.12433},
year = {2019}
}
Comments
To appear in the Electronic Journal of Combinatorics. This version corrects a couple of typos