proposition: Lemma imset_inj (aT rT : finType) (f : aT -> rT) : injective f -> injective (fun A : {set aT} => f @: A).
proof: Proof. move=> inj_f A B eq_AB; apply/setP => x. by rewrite -(mem_imset _ _ inj_f) eq_AB mem_imset. Qed.
imports: Coq(Setoid Morphisms) mathcomp(all_ssreflect) GraphTheory(edone)