proposition: Lemma equivalence_rel_of_sym (T : finType) (e : rel T) : symmetric e -> equivalence_rel (connect e).
proof: Proof. move => sym_e x y z. split => // A. apply/idP/idP; last exact: connect_trans. rewrite connect_symI // in A. exact: connect_trans A. Qed.
imports: Coq(Setoid Morphisms) mathcomp(all_ssreflect) GraphTheory(edone)