proposition: Lemma right_inverse_injectiveC (a b:Set) (s:b->a)(f:a->b): is_right_inverseC f s -> injectiveC s.
proof: Proof. move=> h; apply: inj_if_exists_left_invC; by exists f. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)