proposition: Lemma rpredZsign (S : opprClosed V) n u : ((-1) ^+ n *: u \in S) = (u \in S).
proof: Proof. by rewrite -signr_odd scaler_sign fun_if if_arg rpredN if_same. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)