proposition: Lemma lpreim0 f : (f @^-1: 0)%VS = lker f.
proof: Proof. by rewrite /lfun_preim cap0v limg0 add0v. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop finfun tuple) mathcomp(ssralg matrix mxalgebra zmodp)