The Abu-Khzam$\unicode{x2013}$Langston Conjecture for Graphs with $α(G) = 2$

Abstract

The Abu-Khzam--Langston conjecture, that is the weak-immersion analogue of Hadwiger's conjecture and a weak version of an earlier conjecture of Lescure and Meyniel, asserts that every graph $G$ contains a weak immersion of $K_{χ(G)}$. We prove the conjecture for the class of graphs of independence number two. Along the way, we introduce a notion of \emph{cycle-matching colouring} of a graph, a relaxation of edge-colouring in which colour classes induce vertex-disjoint unions of edges and odd cycles, and prove a sharpening of Vizing's theorem in this setting: every multigraph admits a cycle-matching colouring with at most $Δ(G)$ colours.