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