Almost-Rainbow Edge-Colorings of Some Small Subgraphs

Abstract

Let f(n, p, q) be the minimum number of colors necessary to color the edges of Kn so that every Kp is at least q-colored. We improve current bounds on these nearly “anti-Ramsey” numbers, first studied by Erdös and Gyárfás. We show that , slightly improving the bound of Axenovich. We make small improvements on bounds of Erdös and Gyárfás by showing and for all even n ≢ 1(mod 3), f(n, 4, 5) ≤ n− 1. For a complete bipartite graph G= Kn,n, we show an n-color construction to color the edges of G so that every C4 ⊆ G is colored by at least three colors. This improves the best known upper bound of Axenovich, Füredi, and Mubayi.

Keywords

• ramsey theory
• generalized ramsey theory
• rainbow-coloring
• edge-coloring
• erdös problem