proposition: Lemma lker0_compfV : (f \o f^-1 = \1)%VF.
proof: Proof. by apply/lfunP=> u; rewrite !lfunE /= lker0_lfunVK. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop finfun tuple) mathcomp(ssralg matrix mxalgebra zmodp)