proposition: Lemma raddfMsign n x : f ((-1) ^+ n * x) = (-1) ^+ n * f x.
proof: Proof. by rewrite !(mulr_sign, =^~ signr_odd) (fun_if f) raddfN. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)