Lemma stn_neq_nat_neq { n : nat } (i j : ⟦ n ⟧%stn) : i ≠ j <-> (pr1 i ≠ pr1 j). Proof. split; apply idfun. Defined.
Require Import UniMath.Foundations.All. Require Import UniMath.MoreFoundations.All. Require Import UniMath.Combinatorics.Maybe. Require Import UniMath.Combinatorics.StandardFiniteSets. Require Import UniMath.Algebra.Domains_and_Fields. Require Import UniMath.Algebra.RigsAndRings.