WHEN THE ARC-COLORED LINE DIGRAPH OF A CAYLEY COLORED DIGRAPH IS AGAIN A CAYLEY COLORED DIGRAPH

Let D(DELTA) (G) be the Cayley colored digraph of a finite group G generated by DELTA. The arc-colored line digraph of a Cayley colored digraph is obtained by appropriately coloring the arcs of its line digraph. In this paper it is shown that the group of automorphisms of D(DELTA) (G) that act as permutations on the color classes is isomorphic to the semidirect product of G and a particular subgroup of AutG. Necessary and sufficient conditions for the arc-colored line digraph of a Cayley colored digraph also to be a Cayley colored digraph are then derived.