Properly colored cycles of different lengths in edge-colored complete graphs

Abstract

A cycle in an edge-colored graph is called properly colored if all of its adjacent edges have distinct colors. Let Knc be an edge-colored complete graph with n vertices and let k be a positive integer. Denote by Δmon(Knc) the maximum number of edges of the same color incident with a vertex of Knc. In this paper, we show that (i) if Δmon(Knc)⩽n−2k, then Knc contains k properly colored cycles of different lengths and the bound is sharp; (ii) if Δmon(Knc)⩽n−2k+1−2k+4, then Knc contains k vertex-disjoint properly colored cycles of different lengths; in particular, Δmon(Knc)⩽n−6 suffices for the existence of two vertex-disjoint properly colored cycles of different lengths.