proposition: Lemma induced_sub (G: graph) (S : {set G}) : subgraph (induced S) G.
proof: Proof. exact: subgraph_sub. Qed.
imports: Coq(Morphisms RelationClasses) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij) GraphTheory(equiv digraph setoid_bigop structures)