Paths and cycles in random subgraphs of graphs with large minimum degree

Stefan Ehard¹ ; Felix Joos²

¹Universität Ulm, Germany
²University of Birmingham, United Kingdom

The electronic journal of combinatorics, Tome 25 (2018) no. 2

Résumé

For a graph $G$ and $p\in [0,1]$, let $G_p$ arise from $G$ by deleting every edge mutually independently with probability $1-p$. The random graph model $(K_n)_p$ is certainly the most investigated random graph model and also known as the $G(n,p)$-model. We show that several results concerning the length of the longest path/cycle naturally translate to $G_p$ if $G$ is an arbitrary graph of minimum degree at least $n-1$.For a constant $c>0$ and $p=\frac{c}{n}$, we show that asymptotically almost surely the length of the longest path in $G_p$ is at least $(1-(1+\epsilon(c))ce^{-c})n$ for some function $\epsilon(c)\to 0$ as $c\to \infty$, and the length of the longest cycle is a least $(1-O(c^{- \frac{1}{5}}))n$. The first result is asymptotically best-possible. This extends several known results on the length of the longest path/cycle of a random graph in the $G(n,p)$-model to the random graph model $G_p$ where $G$ is a graph of minimum degree at least $n-1$.

Détail

DOI : 10.37236/6761

Classification : 05C38, 05C80
Mots-clés : graph theory, random graphs, cycles, paths, minimum degree