English

Minimally tough chordal graphs with toughness at most $1/2$

Combinatorics 2023-05-16 v1 Discrete Mathematics

Abstract

Let tt be a positive real number. A graph is called \emph{tt-tough} if the removal of any vertex set SS that disconnects the graph leaves at most S/t|S|/t components. The toughness of a graph is the largest tt for which the graph is tt-tough. A graph is minimally tt-tough if the toughness of the graph is tt and the deletion of any edge from the graph decreases the toughness. A graph is \emph{chordal} if it does not contain an induced cycle of length at least 44. We characterize the minimally tt-tough, chordal graphs for all t1/2t\le 1/2. As a corollary, a characterization of minimally tt-tough, interval graphs is obtained for t1/2t\le 1/2.

Keywords

Cite

@article{arxiv.2209.00376,
  title  = {Minimally tough chordal graphs with toughness at most $1/2$},
  author = {Gyula Y. Katona and Humara Khan},
  journal= {arXiv preprint arXiv:2209.00376},
  year   = {2023}
}