proposition: Lemma unitrP : forall x y, y * x = 1 /\ x * y = 1 -> uam x.
proof: Proof. move=> u v [_ uv1]. by apply/lker0P=> w1 w2 /(congr1 (am v)); rewrite !amE -!mulrA uv1 !mulr1. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(choice fintype div tuple finfun bigop ssralg) mathcomp(finalg zmodp matrix vector poly)