proposition: Lemma minussn1non0 ( n : nat ) ( p : natlth 0 n ) : S ( sub n 1 ) = n.
proof: Proof. revert p. destruct n. - intro p. apply fromempty. exact (isirreflnatlth 0%nat p ). - intro. apply maponpaths. apply minus0r. Defined.
imports: UniMath.Tactics.EnsureStructuredProofs UniMath.Foundations.PartA UniMath.Foundations.Propositions UniMath.Foundations.NaturalNumbers UniMath.Algebra.RigsAndRings UniMath.Algebra.Domains_and_Fields UniMath.NumberSystems.Integers UniMath.Algebra.Monoids