proposition: Lemma rmorph_eq_nat x n : injective f -> (f x == n%:R) = (x == n%:R).
proof: Proof. by move/inj_eq <-; rewrite rmorph_nat. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)