International Journal of Mathematics and Mathematical Sciences
Volume 9 (1986), Issue 2, Pages 409-411
doi:10.1155/S0161171286000510
A digraph equation for homomorphic images
Robert D. Girse
and Richard A. Gillman
Department of Mathematics, Idaho State University, Pocatello 83209, Idaho, USA
Abstract
The definitions of a homomorphism and a contraction of a graph are generalized to digraphs. Solutions are given to the graph equation ϕ(D)¯=θϕ(D¯).