The Linear Combination of Derivations in Prime Rings

In this paper we discuss the linear combination of derivations in prime rings which was initiated by Niu Fengwen. Our aim is to improve Niu's result. For the proof of the main theorem we generalize a result of Bresar and obtain a lemma that is of independent interest.

Cocentralizing Generalized Derivations in Prime Rings

Let R be a prime ring with center Z and S包含 R. Two mappings D and G of R into itself are called cocentralizing on S if D（x）x - xG（x） ∈ Z for all x ∈S. The main purpose of this paper is to describe the structure of generalized derivations which are cocentralizing on ideals, left ideals and Lie ideals of a prime ring, respectively. The semiprime ease is also considered.

Generalized Derivations in Prime Rings

Let R be a ring, a ,b ∈ R, ( D , α ) and (G , β ) be two generalized derivations of R . It is proved that if aD ( x ) = G ( x )b for all x ∈ R, then one of the following possibilities holds: (i) If either a or b is contained in C , then α = β= 0 and there exist p , q ∈ Qr ( RC) such that D ( x )= px and G ( x )= qx for all x ∈ R;(ii) If both a and b are contained in C , then either a = b= 0 or D and G are C-linearly dependent;(iii) If neither a nor b is contained in C , then there exist p , q ∈ Qr ( RC) and w ∈ Qr ( R) such that α ( x ) = [ q ,x] and β ( x ) = [ x ,p] for all x ∈ R, whence D ( x )= wx-xq and G ( x )= xp + avx with v ∈ C and aw-pb= 0.

Left Annihilator of Power Values with Derivations on Lie Ideals in Prime Rings

Let R be a prime ring with characteristic di erent from two,d a derivation of R,L a noncentral Lie ideal of R,and a2R.In the present paper it is showed that if a(d(u^m)±u^m)^n for all u∈L,where m;n are xed positive integers,then a=0 unless R satis es s4,the standard polynomial identity in four variables.

Compositions of Generalized Derivations in Prime Rings

Let R be a prime ring with a non-central Lie ideal L. In the present paper we show that if the composition DG of two generalized derivations D and G is zero on L, then DG must be zero on R. And we get all the possibilities for the composition of a couple of generalized derivations to be zero on a non-central Lie ideal of a prime ring.

Generalized Derivations with Skew Nilpotent Values on Lie Ideals

This article gives characterizations of generalized derivations with skew nilpotent values on noncommutative Lie ideals of a prime ring. The results simultaneously generalize the ones of Herstein, Lee and Carini et al.

An Identity with Skew Derivations on Lie Ideals

Let R be a 2-torsion free prime ring and L a noncommutative Lie ideal of R. Suppose that （d,σ） is a skew derivation of R such that xsd（x）xt = 0 for all x ∈ L, where s, t are fixed non-negative integers. Then d = 0.

LIE IDEALS, MORITA CONTEXT AND GENERALIZED (α, β)-DERIVATIONS

A classical problem in ring theory is to study conditions under which a ring is forced to become commutative. Stimulated from Jacobson＇s famous result, several tech- niques are developed to achieve this goal. In the present note, we use a pair of rings, which are the ingredients of a Morita context, and obtain that if one of the ring is prime with the generalized （α β）-derivations that satisfy certain conditions on the trace ideal of the ring, which by default is a Lie ideal, and the other ring is reduced, then the trace ideal of the reduced ring is contained in the center of the ring. As an outcome, in case of a semi-projective Morita context, the reduced ring becomes commutative.

Strong Commutativity-preserving Generalized Derivations on Semiprime Rings

Let R be a ring with a subset S. A mapping of R into itself is called strong commutativitypreserving （scp） on S, if [f（x）, f（y）] = [x, y] for all x, y ∈ S. The main purpose of this paper is to describe the structure of the generalized derivations which are scp on some ideals and right ideals of a prime ring, respectively. The semiprime case is also considered.

Generalized Derivations Acting on Multilinear Polynomials in Prime Rings and Banach Algebras

Let R be a prime ring of characteristic different from 2 with Utumi quotientring U and extended centroid C,F and G,the two nonzero generalized derivationsof R,I an ideal of R and f(x1,...,xn)a multilinear polynomial over C which is notcentral valued on R.If F(G(f(x1,...,Xn))f(X1,...,Xn))=0 for all x1,...,Xn∈1,then one of the followings holds:(1)there exist a,b c Usuch that F(x)=ax and G(x)=bx for all x c R with ab=0;(2)there exista,b,p c U such that F(x)=ax+xb and G(x)=px for all x c R with F(p)=0and f(x1,...,xn)’is central valued on R.We also obtain some related results in caseswhere R is a semiprime ring and Banach algebra.

b-Generalized Derivations Acting on Multilinear Polynomials in Prime Rings

Let R be a prime ring of characteristic different from 2,Q be its maximal right ring of quotients,and C be its extended centroid.Suppose that f(x1,...,xn)is a non-central multilinear polynomial over C,0≠p∈R,and F,G are two b-generalized derivations of R.In this paper we describe all possible forms of F and G in the case pG(F(f(r))f(r))=0 for all r=(r1,...,rn)in R^n.

Centralizers of X-Generalized Skew Derivations on Multilinear Polynomials in Prime Rings

Let R be a prime ring of characteristic different from 2,Q_(r) be its right MartindalequotientringandC beitsextendedcentroid,G beanonzero X-generalized skew derivation of R,and S be the set of the evaluations of a multilinear polynomial f(x_(1),...,x_(n))over C with n non-commuting variables.Let u,v∈R be such that uG(x)x+G(x)xv=0 for all x∈S.Then one of the following statements holds:(a)v∈C and there exist a,b,c∈Q_(r) such that G(x)=ax+bxc for any x∈R with(u+v)a=(u+v)b=0;(b)f(x_(1),...,x_(n))2 is central-valued on R and there exists a∈Q r such that G(x)=ax for all x∈R with ua+av=0.

On the Derivations of Semiprime Rings and Noncommutative Banach Algebras

Let A be a noncommutative Banach algebra.Suppose there exists a continuous linear Jordan derivation D:A→A such that [D(x),x]D(x)[D(x),x]∈ rad(A) for all x ∈ A.In this case, D(A)rad(A).

A note on generalized Lie derivations of prime rings

Let R be a prime ring of characteristic not 2, A be an additive subgroup of R, and F, T, D, K： A →R be additive maps such that F（[x, y]） = F（x）y - yg（x） - T（y）x ＋ xD（y） for all x, y ∈ A. Our aim is to deal with this functional identity when A is R itself or a noncentral Lie ideal of R. Eventually, we are able to describe the forms of the mappings F, T, D, and K in case A = R with deg（R） 〉 3 and also in the case A is a noncentral Lie ideal and deg（R） 〉 9. These enable us in return to characterize the forms of both generalized Lie derivations, D-Lie derivations and Lie centralizers of R under some mild assumptions. Finally, we give a generalization of Lie homomorphisms on Lie ideals.

Some Results about Derivations of Prime Rings

Recently, basing on a suitable application of Milne-Bhatnagar＇s characterization theorem about matrix inversions, we have found that Warnaar＇s elliptic matrix inversion can be further extended to the following general inversion theorem.

Prime Rings with Generalized Derivations

The concept of derivations and generalized inner derivations has been generalized as an additive function δ： R → R satisfying δ （xy） = δ（x）y＋xd（y） for all x, y ∈ R, where d is a derivation on R. Such a function δ is called a generalized derivation. Suppose that U is a Lie ideal of R such that u^2 ∈ U for all u ∈ U. In this paper, we prove that U lahtain in Z（R） when one of the following holds： （1） δ（[u, v]） = u o v =（2） δ（[u,v]）=[u o v] = 0 （3） δ（u o v） = [u, v] （4） δ（u o v）＋δ[u, v] = 0 for all u, v ∈ U.

On Generalized （m, n）-Derivations and Generalized （m, n）-Jordan Derivations in Rings

The aim of this paper is to define the notions of generalized （m, n）-derivations and generalized （m, n）：Jordan derivations and to prove two theorems involving these map- pings.

Commutativity of Near-rings with Derivations

In this paper we first prove that a near-ring admits a derivation if and only if it is zero-symmetric. Also, we prove some commutativity theorems for a non-necessarily 3-prime near-ring R with a suitably-constrained derivation d satisfying the condition that d（a） is not a left zero-divisor in R for some a ∈ R. As consequences, we generalize several commutativity theorems for 3-prime near-rings admitting derivations.

Generalized Derivations in Rings with Involution

The main purpose of this paper is to study generalized derivations in rings with involution which behave like strong commutativity preserving mappings. In fact, we prove the following result： Let R be a noncommutative prime ring with involution of the second kind such that char（R） ≠ 2. If R admits a generalized derivation F ： R → R associated with a derivation d ： R → R such that [F（x）,F（x＊）] - [x,x＊] = 0 for all x ∈ R, then F（x）= x for all x ∈ R or F（x） = -x for all x ∈ R. Moreover, a related result is also obtained.

Derivations as Homomorphisms or Anti-homomorphisms on Lie Ideals

Let R be a 2-torsion free prime ring, Z the center of R, and U a nonzero Lie ideal of R. If d is a derivation of R which acts as a homomorphism or an anti-homomorphism on U, then either d = 0 or U lohtein in Z. This result improves a theorem of Asma, Rehman, and Shakir.