Rainbow degree-jump coloring of graphs

Keywords:
rainbow degree-jump coloring, rainbow degree-jump chromatic number, blind vertex, Mphako graph, Moore boundAbstract
In this paper, we introduce a new notion called the rainbow degree-jump coloring of a graph. For a vertex v∈V(G), let the degree-jump closed neighbourhood of a vertex v be defined as Ndeg[v]={u:d(v,u)≤d(v)}. A proper coloring of a graph G is said to be a rainbow degree-jump coloring of G if for all v in V(G), c(Ndeg[v]) contains at least one of each color class. We determine a necessary and sufficient condition for a graph G to permit a rainbow degree-jump coloring. We also determine the rainbow degree-jump chromatic number, denoted by χrdj(G), for certain classes of cycle related graphs.