A note on derivations in semiprime rings

We prove in this note the following result. Let n>1 be an integer and let R be an n!-torsion-free semiprime ring with identity element. Suppose that there exists an additive mapping D:R→R such that D(xn)=∑j=1nxn−jD(x)xj−1 is fulfilled for all x∈R. In this case, D is a derivation. This research is...

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Main Authors: Joso Vukman, Irena Kosi-Ulbl
Format: Article
Language:English
Published: Wiley 2005-01-01
Series:International Journal of Mathematics and Mathematical Sciences
Online Access:http://dx.doi.org/10.1155/IJMMS.2005.3347
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author Joso Vukman
Irena Kosi-Ulbl
author_facet Joso Vukman
Irena Kosi-Ulbl
author_sort Joso Vukman
collection DOAJ
description We prove in this note the following result. Let n>1 be an integer and let R be an n!-torsion-free semiprime ring with identity element. Suppose that there exists an additive mapping D:R→R such that D(xn)=∑j=1nxn−jD(x)xj−1 is fulfilled for all x∈R. In this case, D is a derivation. This research is motivated by the work of Bridges and Bergen (1984). Throughout, R will represent an associative ring with center Z(R). Given an integer n>1, a ring R is said to be n-torsion-free if for x∈R, nx=0 implies that x=0. Recall that a ring R is prime if for a,b∈R, aRb=(0) implies that either a=0 or b=0, and is semiprime in case aRa=(0) implies that a=0. An additive mapping D:R→R is called a derivation if D(xy)=D(x)y+xD(y) holds for all pairs x,y∈R and is called a Jordan derivation in case D(x2)=D(x)x+xD(x) is fulfilled for all x∈R. Every derivation is a Jordan derivation. The converse is in general not true. A classical result of Herstein (1957) asserts that any Jordan derivation on a prime ring with characteristic different from two is a derivation. A brief proof of Herstein's result can be found in 1988 by Brešar and Vukman. Cusack (1975) generalized Herstein's result to 2-torsion-free semiprime rings (see also Brešar (1988) for an alternative proof). For some other results concerning derivations on prime and semiprime rings, we refer to Brešar (1989), Vukman (2005), Vukman and Kosi-Ulbl (2005).
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spelling doaj-art-bb06b71826694554bb039e9a1dcb2c732025-02-03T05:45:33ZengWileyInternational Journal of Mathematics and Mathematical Sciences0161-17121687-04252005-01-012005203347335010.1155/IJMMS.2005.3347A note on derivations in semiprime ringsJoso Vukman0Irena Kosi-Ulbl1Department of Mathematics, Faculty of Education, University of Maribor, Koroška Cesta 160, Maribor 2000, SloveniaDepartment of Mathematics, Faculty of Education, University of Maribor, Koroška Cesta 160, Maribor 2000, SloveniaWe prove in this note the following result. Let n>1 be an integer and let R be an n!-torsion-free semiprime ring with identity element. Suppose that there exists an additive mapping D:R→R such that D(xn)=∑j=1nxn−jD(x)xj−1 is fulfilled for all x∈R. In this case, D is a derivation. This research is motivated by the work of Bridges and Bergen (1984). Throughout, R will represent an associative ring with center Z(R). Given an integer n>1, a ring R is said to be n-torsion-free if for x∈R, nx=0 implies that x=0. Recall that a ring R is prime if for a,b∈R, aRb=(0) implies that either a=0 or b=0, and is semiprime in case aRa=(0) implies that a=0. An additive mapping D:R→R is called a derivation if D(xy)=D(x)y+xD(y) holds for all pairs x,y∈R and is called a Jordan derivation in case D(x2)=D(x)x+xD(x) is fulfilled for all x∈R. Every derivation is a Jordan derivation. The converse is in general not true. A classical result of Herstein (1957) asserts that any Jordan derivation on a prime ring with characteristic different from two is a derivation. A brief proof of Herstein's result can be found in 1988 by Brešar and Vukman. Cusack (1975) generalized Herstein's result to 2-torsion-free semiprime rings (see also Brešar (1988) for an alternative proof). For some other results concerning derivations on prime and semiprime rings, we refer to Brešar (1989), Vukman (2005), Vukman and Kosi-Ulbl (2005).http://dx.doi.org/10.1155/IJMMS.2005.3347
spellingShingle Joso Vukman
Irena Kosi-Ulbl
A note on derivations in semiprime rings
International Journal of Mathematics and Mathematical Sciences
title A note on derivations in semiprime rings
title_full A note on derivations in semiprime rings
title_fullStr A note on derivations in semiprime rings
title_full_unstemmed A note on derivations in semiprime rings
title_short A note on derivations in semiprime rings
title_sort note on derivations in semiprime rings
url http://dx.doi.org/10.1155/IJMMS.2005.3347
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