proposition: Theorem associativityNat : isAssociative_fun 0 add.
proof: Proof. intros n m x. unfold iterop_fun_fun. apply pathsinv0. rewrite 2 iterop_fun_nat. intermediate_path (stnsum (λ i : stn n, stnsum (x i))). - apply maponpaths. apply funextfun; intro. apply iterop_fun_nat. - now apply nat_plus_associativity'. Defined.
imports: UniMath.Combinatorics.Lists UniMath.Combinatorics.FiniteSequences UniMath.Algebra.RigsAndRings UniMath.Foundations.UnivalenceAxiom UniMath.MoreFoundations.Tactics UniMath.Algebra.Groups UniMath.MoreFoundations.NegativePropositions UniMath.Combinatorics.FiniteSets UniMath.Foundations.NaturalNumbers