proposition: Lemma findex_bound (x y : T) n : iter n f x = y -> findex f x y <= n.
proof: Proof. move => iter_n; have f_xy: fconnect f x y by rewrite -iter_n fconnect_iter. by apply: contra_eqT iter_n; rewrite -ltnNge; apply: before_findex. Qed.
imports: Coq(Setoid Morphisms) mathcomp(all_ssreflect) GraphTheory(edone)