On structure and commutativity of certain periodic near rings

In the present paper we first establish decomposition theorems for near rings satisfying either of the properties xy = x^my^pxⁿ or xy = y^mx^pyⁿ, where m≥1, n≥1, p≥1 are positive integers depending on the pair of near ring elements x,y; and further, we investigate commutativity of such near rings. Moreover, it is also shown that under some additional hypotheses, such nearrings turn out to be commutative rings.     

Generating elements and defining relations for symplectic groups over certain rings

We determine the generating elements and defining relations for symplectic groups over local rings in which each finitely generated right ideal is principal.     

Modules over group rings of soluble groups with a certain condition of maximality

Let A be an R G-module, where R is an integral domain and G is a soluble group. Suppose that C _G (A) = 1 and A/C _A (G) is not a noetherian R-module. Let L _nnd(G) be the family of all subgroups H of G such that A/C _A (H) is not a noetherian R-module. In this paper we study the structure of those G for which L _nnd(G) satisfies the maximal condition.     

Factorization in certain Cayley rings

There are, up to isomorphism, three rings of integral elements of the Cayley algebra over the rationals which contain the naive Cayley ring as a proper subring. This paper studies factorizations in each of these rings in a manner analogous to that in an earlier study by Pall and Taussky.     

Finitely additive measures on groups and rings

On topological groups a natural finitely additive measure can be defined via compactifications. It is closely related to Hartman's concept of uniform distribution on non-compact groups (cf. [3]). Applications to several situations are possible. Some results of M. Paštéka and other authors on uniform distribution with respect to translation invariant finitely additive probability measures on Dedekind domains are transferred to more general situations. Furthermore it is shown that the range of a polynomial of degree ≥2 on a ring of algebraic integers has measure 0.     

IBN rings and orderings on grothendieck groups

LetR be a ring with an identity element.R∈IBN means thatR ^m⋟Rⁿ impliesm=n, R∈IBN ₁ means thatR ^m⋟Rⁿ⊕K impliesm≥n, andR∈IBN ₂ means thatR ^m⋟R^m⊕K impliesK=0. In this paper we give some characteristic properties ofIBN ₁ andIBN ₂, with orderings on the Grothendieck groups. In addition, we obtain the following results: (1) IfR∈IBN ₁ and all finitely generated projective leftR-modules are stably free, then the Grothendieck groupK ₀(R) is a totally ordered abelian group. (2) If the pre-ordering of the Grothendieck groupK ₀(R) of a ringR is a partial ordering, thenR∈IBN ₁ orK ₀(R)=0. Supported by National Nature Science Foundation of China.     

群,环上的Fuzzy关系

一些学者已对群和环上的Ｆｕｚｚｙ关系进行了研究，本文进一步研究了群、环上的Ｆｕｚｚｙ关系，得出了若干重要的结论。