proposition: Lemma iter_addr n x y : iter n (+%R x) y = x *+ n + y.
proof: Proof. by elim: n => [|n ih]; rewrite ?add0r //= ih mulrS addrA. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)