 
Summary: Journal of Pure and Applied Algebra 210 (2007) 8191
www.elsevier.com/locate/jpaa
On deformations of crossed products
Eli Aljadeffa,, Yuval Ginosarb, Andy R. Magidc
a Department of Mathematics, TechnionIsrael Institute of Technology, Haifa 32000, Israel
b Department of Mathematics, University of Haifa, Haifa 31905, Israel
c Department of Mathematics, University of Oklahoma, Norman 73019, OK, USA
Received 12 October 2005; received in revised form 2 August 2006
Available online 5 October 2006
Communicated by C. Kassel
Abstract
Let A be a crossed product algebra, where A is semisimple, finitely generated over its center and is a finite group. We
give a necessary and sufficient condition in terms of the outer action of on A for the existence of a multiparametric semisimple
deformation of the form A((t1, . . . , tn)) (with the induced outer action). The main tool in the proof is the solution of the
socalled twisting problem. We also give an example which shows that the condition is not sufficient if one drops the condition on
the finite generation of A over its center.
c 2006 Elsevier B.V. All rights reserved.
MSC: 16K20
1. Introduction
Let R = A be a crossed product algebra, where A is an artinian ring, finitely generated over its center, and
