proposition: Lemma fmP m1 m2 : (m1 == m2) = (m1 == m2 :> seq I).
proof: Proof. by rewrite val_eqE. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq path choice finset fintype finfun) mathcomp(tuple bigop ssralg ssrint ssrnum) xfinmap