Homomorphisms and related contractions of graphs

[摘要] For every homomorphismϕof a graphGthere exists a contractionθϕonG¯, the complement ofG. Here we study the graph equationϕ(G)=θϕ(G¯). In the course of our work we show that Hadwiger's Conjecture is true for every self-complementary graph.

[学科分类] 数学（综合）