proposition: Lemma denom_ratioP : forall f : ratio, f.2 != 0.
proof: Proof. by case. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(ssrAC choice tuple bigop ssralg poly polydiv) mathcomp(generic_quotient)