fact: Definition min_imperfect_mem (G : sgraph) (A : mem_pred G) := (omega_mem A < chi_mem A) && [forall (B : {set G} | B \proper A), perfect B].
imports: mathcomp(all_ssreflect) GraphTheory(preliminaries bij digraph sgraph) GraphTheory(dom partition coloring) mathcomp(ssrint) mathcomp(all_algebra)