Definition dni_lastelement {n : nat} : ⟦n⟧ -> ⟦S n⟧. Proof. intros h. exists (pr1 h). exact (natlthtolths _ _ (pr2 h)). Defined.
Require Import UniMath.MoreFoundations.Tactics. Require Import UniMath.MoreFoundations.DecidablePropositions. Require Import UniMath.MoreFoundations.NegativePropositions.