In this paper, we consider the finitely presented groups Gm and K(s, l) as follows; Gm = 〈a, b|a = b = 1, [a, b] = [a, b], [a, b] = [a, b]〉 K(s, l) = 〈a, b|ab = ba, ba = ab〉; and find the n-commutativity degree for each of them. Also we study the concept of n-abelianity on these groups, where m,n, s and l are positive integers, m,n ≥ 2 and g.c.d(s, l) = 1.

It is shown that coherence conditions for monoidal categories concerning associativity are analogous to coherence conditions for symmetric strictly monoidal categories, where associativity arrows are identities. Mac Lane’s pentagonal coherence condition for associativity is decomposed into conditions concerning commutativity, among which we have a condition analogous to naturality and a degener...

It is shown that coherence conditions for monoidal categories concerning associativity are analogous to coherence conditions for symmetric strictly monoidal categories, where associativity arrows are identities. Mac Lane’s pentagonal coherence condition for associativity is decomposed into conditions concerning commutativity, among which we have a condition analogous to naturality and a degener...

It is shown that all the assumptions for symmetric monoidal categories flow out of a unifying principle involving natural isomorphisms of the type (A ∧B) ∧ (C ∧D) → (A ∧ C) ∧ (B ∧D), called medial commutativity. Medial commutativity in the presence of the unit object enables us to define associativity and commutativity natural isomorphisms. In particular, Mac Lane’s pentagonal and hexagonal coh...

We present a technique for automatically generatingcommutativity conditions from (abstract-level) data-structurespecifications. We observe that one can pose the commutativityquestion in a way that does not introduce additional quantifiers,via a mechanized lifting of a (potentially partial) specificationto an equivalent total specification. We then describe an al-gorithm ...

The fundamental updating process in the tmnsfemble belief model is related to Lhe concept of specialization and can be described by a specialization matrix. The degree of belief in the truth of a proposition is a degree of justified support. The Principle of Minimal Commitment implies that one should never give more support to the truth of a proposition than justified. We show that Dempster's r...

We present some formal properties of (symmetrical) commutativity, the major criterion used in transactional systems, which allow us to fully understand its advantages and disadvantages. The main result is that commutativity is subject to the same limitation as compatibility for arbitrary objects. However, commutativity has also a number of attracting properties, one of which is related to recov...