On (1,l)-coloring of incidentors of multigraphs

Abstract

It is proved that if l is at least Δ/2 − 1 then (1, l)-chromatic number of an arbitrary multigraph of maximum degree Δ is at most Δ+1. Moreover, it is proved that the incidentors of every directed prism can be colored in four colors so that every two adjacent incidentors are colored distinctly and the difference between the colors of the final and initial incidentors of each arc is 1.