proposition: Lemma induction_defined_pr s a (f := induction_defined s a): [/\ source f = Nat, surjection f, Vf f \0c = a & forall n, natp n -> Vf f (csucc n) = s (Vf f n)].
proof: Proof. exact: (induction_defined_pr0 (fun u v => s v) a). Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(binomial div)