proposition: Lemma memv_sum_pi i v : sumv_pi_for defV i v \in Vs i.
proof: Proof. rewrite /sumv_pi_for. elim: (filter P r0) v => [|j r IHr] v /=; first by rewrite lfunE mem0v. by case: eqP => [->|_]; rewrite ?lfunE ?memv_pi1 /=. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop finfun tuple) mathcomp(ssralg matrix mxalgebra zmodp)