Definition stn_left' (m n : nat) : m ≤ n -> ⟦m⟧ -> ⟦n⟧. Proof. intros le i. exact (make_stn _ _ (natlthlehtrans _ _ _ (stnlt i) le)). Defined.
Require Import UniMath.MoreFoundations.Tactics. Require Import UniMath.MoreFoundations.DecidablePropositions. Require Import UniMath.MoreFoundations.NegativePropositions.