WORM colorings of planar graphs
Július Czap, Stanislav Jendrol′, Juraj Valiska · Discussiones Mathematicae Graph Theory · 2016
Given three planar graphs F, H, and G, an (F, H)-WORM coloring of G is a vertex coloring such that no subgraph isomorphic to F is rainbow and no subgraph isomorphic to H is monochromatic. If G has at least one (F, H)-WORM coloring, then W - F,H (G) denotes the minimum number of colors in an (F, H)-WORM coloring of G. We show that (a)