proposition: Fact mulVZ : {in unitZ, left_inverse 1%R invZ *%R}.
proof: Proof. by move=> n /pred2P[] ->. Qed.
imports: Coq(ZArith) HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(div choice fintype tuple finfun bigop finset prime) mathcomp(order binomial ssralg countalg ssrnum ssrint) mathcomp(zify_ssreflect)