proposition: Lemma exprNn x n : (- x) ^+ n = (-1) ^+ n * x ^+ n :> R.
proof: Proof. by rewrite -mulN1r exprMn_comm // /comm mulN1r mulrN mulr1. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)