proposition: Lemma mulmorV (phi : 'Iso(M,N)) : phi ** phi^^-1 %= idm.
proof: Proof. by rewrite /invmor; case: sigW => /= psi /andP []. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq path) mathcomp(ssralg fintype perm choice matrix bigop zmodp mxalgebra poly) ssrcomplements stronglydiscrete coherent edr