proposition: Fact lfun_mulrRV f : lker f == 0%VS -> f * lfun_invr f = 1.
proof: Proof. by move=> Uf; rewrite /lfun_invr Uf lfun_mulrV. 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)