Chi-boundedness of graph classes excluding wheel vertex-minors
Speaker:
Sang-il Oum, KAIST
Date and Time:
Thursday, October 12, 2017 - 1:30pm to 1:55pm
Location:
Fields Institute, Room 230
Abstract:
A class of graphs is $\chi$-bounded if there exists a function $f:\mathbb N\rightarrow \mathbb N$ such that for every graph $G$ in the class and an induced subgraph $H$ of $G$, if $H$ has no clique of size $q+1$, then the chromatic number of $H$ is less than or equal to $f(q)$. We denote by $W_n$ the wheel graph on $n+1$ vertices. We show that the class of graphs having no vertex-minor isomorphic to $W_n$ is $\chi$-bounded. This generalizes several previous results; $\chi$-boundedness for circle graphs, for graphs having no $W_5$ vertex-minors, and for graphs having no fan vertex-minors. This is a joint work with Hoijn Choi, O-joung Kwon, and Paul Wollan.