proposition: Lemma mpoly_inv_out : {in [predC mpoly_unit], mpoly_inv =1 id}.
proof: Proof. by rewrite /mpoly_inv => p /negbTE /= ->. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(choice fintype tuple finfun bigop finset binomial) mathcomp(order fingroup perm ssralg zmodp poly ssrint) mathcomp(matrix vector) mathcomp(bigenough) ssrcomplements freeg