Injective edge coloring of graphs


Domingos M Cardoso, J Orestes Cerdeira, Charles Dominic, J Pedro Cruz




Three edges e1, e2 and e3 in a graph G are consecutive if they form a path (in this order) or a cycle of lengths three. An injective edge coloring of a graph G = (V,E) is a coloring c of the edges of G such that if e1, e2 and e3 are consecutive edges in G, then c(e1) , c(e3). The injective edge coloring number χ ′ i (G) is the minimum number of colors permitted in such a coloring. In this paper, exact values of χ ′ i (G) for several classes of graphs are obtained, upper and lower bounds for χ′i (G) are introduced and it is proven that checking whether χ′i (G) = k is NP-complete