proposition: Lemma lker0_amull u : u \is a GRing.unit -> lker (amull u) == 0%VS.
proof: Proof. by move=> Uu; apply/lker0P=> v w; rewrite !lfunE; apply: mulrI. 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)