Posner and herstein theorems for derivations of 3-prime near-rings

The analog of Posner's theorem on the composition of two derivations in prime rings is proved for 3-prime near-rings. It is shown that if d is a nonzero derivation of a 2-torsionfree 3-prime near-ring N and an element a ? N is such that ax^d = x^da for all x ? N, then a is a central element. As a consequence it is shown that if d\ and d₂ are nonzero derivations of a 2-torsionfree 3-prime near-ring N and x^d1y^d2 = y^d2x^d1 for all x, y ? N, then N is a commutative ring. Thus two theorems of Herstein are generalized     

On zero-divisors of near-rings of polynomials

In this paper, we are interested to study zero-divisor properties of a 0-symmetric nearring of polynomials R₀[x], when R is a commutative ring. We show that for a reduced ring R, the set of all zero-divisors of R₀[x], namely Z(R₀[x]), is an ideal of R₀[x] if and only if Z(R) is an ideal of R and R has Property (A). For a non-reduced ring R, it is shown that Z(R₀[x]) is an ideal of Z(R₀[x]) if and only if ann_R({a, b}) ∩ N i?(R) ≠ 0, for each a, b ∈ Z(R). We also investigate the interplay between the algebraic properties of a 0-symmetric nearring of polynomials R₀[x] and the graph-theoretic properties of its zero-divisor graph. The undirected zero-divisor graph of R₀[x] is the graph Γ(R₀[x]) such that the vertices of Γ(R₀[x]) are all the non-zero zero-divisors of R₀[x] and two distinct vertices f and g are connected by an edge if and only if f ? g = 0 or g ? f = 0. Among other results, we give a complete characterization of the possible diameters of Γ(R₀[x]) in terms of the ideals of R. These results are somewhat surprising since, in contrast to the polynomial ring case, the near-ring of polynomials has substitution for its “multiplication” operation.     

Radical theory in varieties of near-rings in which the constants form

Not all the good properties of the Kurosh-Amitsur radical theory in the variety of associative rings are preserved in the bigger variety of near-rings. In the smaller and better behaved variety of O-symmetric near-rings the theory is much more satisfactory. In this note we show that many of the results of the 0-symmetric near-ring case can be extended to a much bigger variety of near-rings which, amongst others, includes all the O-symmetric as well as the constant near-rings. The varieties we shall consider are varieties of near-rings, called Fuchs varieties, in which the constants form an ideal. The good arithmetic of such varieties makes it possible to derive more explicit conditions.

(i) for the subvariety of constant near-rings to be a semisimple class (or equivalently, to have attainable identities),

(ii) for semisimple classes to be hereditary.

We shall prove that the subvariety of 0-symmetric near-rings has attainable identities in a Fuchs variety, and extend the theory of overnilpotent radicals of 0-symmetric near-rings to the largest Fuchs variety F

The near-ring construction of [7] will play a decisive role in our investigations.     

ZS-metacyclic groups and their endomorphism near-rings

ItG is a group written additively, the inner automorphisms and the endomorphisms additively generate near-ringsI(G) andE(G) respectively. IfI(G)=E(G), i.e., if every endomorphism is a sum of inner automorphisms, we callG anI-E group. In this paper we describe a class ofI-E groups which includes two of the four known classes ofI-E groups and which contains infinitely many other examples. The order ofI(G) is obtained and its radical determined.Supported in part by the Natural Sciences and Engineering Research Council of Canada.     

Prime ideals and prime radicals in near-rings

This paper investigates conditions under which a prime ideal is completely prime and conditions for which every prime ideal in a near-ring is completely prime. Various implications of these conditions are examined with respect to the associated radicals.     

Distributor and j2-radical ideals of generalized centralizer near-rings

In 1980, Maxson and Smith [1] determined the J₂-radical ideal for the ceiitralizer near-ring M_A(G), where A is a group of automorphisms over a group G. Further, in 1985, Smith [4] generalized MA(G) to the class of generalized ceiitralizer near-rings. In this paper we determine both the J₂-radical and the distributor ideals for the class of generalized ceiitralizer near-rings. We further push these results to determine all the homomorphie images of generalized ceiitralizer near-rings.     

Centralizer near-rings determined by PID-modules,II

We answer an open problem in radical theory by showing that there exists a zero-symmetric simple near-ringN with identity such thatJ ₂(N)=N.To 80^th birthday of Paul Erds     

The general radical theory of near-rings — answers to some open problems

It is shown that in the variety of all, not necessarily 0-symmetric near-rings, there are no non-trivial classes of near-rings which satisfy condition (F), no non-trivial (Kurosh-Amitsur) radical classes with the ADS-property and consequently no non-trivial ideal-hereditary radical classes. It is also shown that any hereditary semisimple class contains only 0-symmetric near-rings.Presented by E. Fried.AMS Subject Classification: 16Y30; 16N80.     

A lattice isomorphism between sets of ideals of the near-rings in a near-ring morita context

We establish a one-to-one correspondence between certain sets of ideals of two near-rings L and R respectively if they form a near-ring morita context (L,G,H,R) for some groups G and H.     

Kurosh–Amitsur Right Jacobson Radicals of Type-1 and 2 for Right Near-Rings

Near-rings considered are right near-rings. Let ν ∈ {1, 2}. J ^r _ν , the right Jacobson radical of type-ν, was introduced for near-rings by the first and second authors. In this paper properties of these radicals J ^r _ν are studied. It is shown that J ^r _ν is a Kurosh-Amitsur radical (KA-radical) in the variety of all near-rings R in which the constant part R _c of R is an ideal of R. Thus, unlike the left Jacobson radical of type-1 of near-rings, J ^r ₁ is a KA-radical in the class of all zero-symmetric near-rings. J ^r _ν is not s-hereditary and hence not an ideal-hereditary radical in the class of all zero-symmetric near-rings. Received: April 1, 2007. Revised: July 11, 2007.     

Special radicals of near-rings and Γ-near-rings

It was previously shown that every special radical classR of rings induces a special radical class R of -rings. Amongst the special radical classes of near-rings, there are some, called the -special radical classes, which induce, special radical classes of -near-rings by the same procedure as used in the ring case. The -special radicals of near-rings possess very strong hereditary properties. In particular, this leads to some new results for the equiprime andI ₃ radicals.     

D-strong and almostD-strong near-rings

In this paper,D-strong and almostD-strong near-rings have been defined. It has been proved that ifR is aD-strongS-near ring, then prime ideals, strictly prime ideals and completely prime ideals coincide. Also ifR is aD-strong near-ring with identity, then every maximal right ideal becomes a maximal ideal and moreover every 2-primitive near-ring becomes a near-field. Several properties, chain conditions and structure theorems have also been discussed.Most of the parts of this paper are included in author's doctoral dissertation at Sukhadia University Udaipur (1983). The author expresses his gratitude to Dr.S. C. Choudhary for his kind guidance.     

Existence of derivations on near-rings

We obtain conditions on (R,+) which force that the zero map is the only derivation on a zero-symmetric near-ring R. Throughout the paper we construct several new examples of near-rings which are not rings admitting non-zero derivations, non-zero (σ, σ)-derivations and non-zero (1, σ)-derivations.     

On Polynomials Over Rickart Rings and Their Generalizations I

This paper continues the investigation of polynomials and formal power series over a ring with various annihilator conditions which were originally used by Rickart and Kaplansky to abstract the algebraic properties of von Neumann algebras. Results of Armendariz on polynomial rings over a PP ring are extended to analogous annihilator conditions in nearrings of polynomials and nearrings of formal power series. These results are somewhat striking since, in contrast to the polynomial ring case, the nearring of polynomials or formal power series has substitution for its “multiplication” operation. These investigations provide an alternative viewpoint in illustrating the structure of polynomials and formal power series. Extensions of Rickart rings to formal power series rings are also discussed. The author was partially supported by the National Science Council, Taiwan under the grant number NSC 93-2115-M-143-001.     

Annihilator Conditions on Polynomials II

In this paper, we continue the study of various annihilator conditions which were used by Rickart and Kaplansky to abstract the algebraic properties of von Neumann algebras. In our main results, we extend results of Armendariz on the Baer and p.p. conditions in a polynomial ring to certain analogous annihilator conditions in a nearring of polynomials. These results are somewhat surprising since, in contrast to the polynomial ring case, the nearring of polynomials has substitution for its multiplication operation. Moreover they indicate connections between the ring and nearring structures on polynomials. Examples are provided to illustrate and delimit our results.This revised version was published online in October 2004 with a corrected Received date.The second author was partially supported by the National Science Council of the Republic of China, Taiwan under grant number NSC 90-2115-M-143-001.     

The fraction of the bijections generating the near-ring of 0-preserving functions

Let 〈G, +〉 be a finite (not necessarily abelian) group. Then M₀(G) := {f : G → G| f (0) = 0} is a near-ring, i.e., a group which is also closed under composition of functions. In Theorem 4.1 we give lower and upper bounds for the fraction of the bijections which generate the near-ring M₀(G). From these bounds we conclude the following: If G has few involutions and the order of G is large, then a high fraction of the bijections generate the near-ring M₀(G). Also the converse holds: If a high fraction of the bijections generate M₀(G), then G has few involutions (compared to the order of G). Received: 10 January 2005     

The semidirect products of finite cyclic groups that areI-E groups

AnI-E group is a group in which the endomorphism near-ring generated by the group's inner automorphisms equals the endomorphism near-ring generated by its endomorphisms. In this paper we shall completely determine the finite groups that are semidirect products of cyclic groups and areI-E groups.     

Generalized complex numbers over near-fields

The construction of the complex numbers over the reals has been generalized in many ways leading, amongs others, to the 2-dimensional elliptical complex numbers (= ordinary complex numbers), the parabolic complex numbers and the hyperbolic complex numbers. One can extend these to higher dimensions and also to using an arbitrary ring as the base ring. Here we propose a construction of generalized complex numbers over a near-field and investigate some of the structural properties of this near-ring.     

MORITA NEAR-RINGS

Abstract

We define a morita context for near-rings and subsequently a morita near-ring. Any near-ring can be considered as a morita context for near-rings, and the corresponding morita near-ring is just the 2 x 2 matrix near-ring over the near-ring. We also determine the relationships between the ideals of a morita context and the ideals of a morita near-ring.