fact: Variables (G : graph) (V1 V2 : {set G}) (E1 E2 : {set edge G}) (con1 : consistent V1 E1) (con2 : consistent V2 E2) (h : pairs (subgraph_for con1 ⊎ subgraph_for con2)%G).
imports: Coq(Morphisms RelationClasses) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij) GraphTheory(equiv digraph setoid_bigop structures)