proposition: Lemma memvN U v : (- v \in U) = (v \in U).
proof: Proof. exact: rpredN. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop finfun tuple) mathcomp(ssralg matrix mxalgebra zmodp)