Lemma negweqstnsn0 (n : nat) : ¬ (⟦S n⟧ ≃ stn O). Proof. unfold neg. assert (lp: ⟦S n⟧) by apply lastelement. intro X. apply weqstn0toempty. apply (pr1 X lp). Defined.
Require Import UniMath.MoreFoundations.Tactics. Require Import UniMath.MoreFoundations.DecidablePropositions. Require Import UniMath.MoreFoundations.NegativePropositions.