proposition: Lemma stn_eq_or_neq_left {n} {i j: (⟦ n ⟧)%stn} : forall p : i = j, stn_eq_or_neq i j = inl p.
proof: Proof. intros; apply isaprop_stn_eq_or_neq. Defined.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.Combinatorics.Maybe UniMath.Combinatorics.StandardFiniteSets UniMath.Algebra.Domains_and_Fields UniMath.Algebra.RigsAndRings