proposition: Lemma stnprod_eq {n : nat} (f g: ⟦n⟧ -> nat) : f ~ g -> stnprod f = stnprod g.
proof: Proof. intros h. induction n as [|n IH]. { apply idpath. } rewrite 2? stnprod_step. induction (h lastelement). apply (maponpaths (λ i, i * f lastelement)). apply IH. intro x. apply h. Defined.
imports: UniMath.Foundations.NaturalNumbers UniMath.MoreFoundations.Tactics UniMath.MoreFoundations.DecidablePropositions UniMath.MoreFoundations.NegativePropositions