Definition weqdnicoprod_map {n : nat} (j : ⟦S n⟧ ) : ⟦n⟧ ⨿ unit -> ⟦S n⟧. Proof. intros x. induction x as [i|t]. - exact (dni j i). - exact j. Defined.
Require Import UniMath.MoreFoundations.Tactics. Require Import UniMath.MoreFoundations.DecidablePropositions. Require Import UniMath.MoreFoundations.NegativePropositions.