Fixed Rings of Finite Automorphism Groups of Associative Rings

  • PDF / 4,169,016 Bytes
  • 133 Pages / 461 x 684 pts Page_size
  • 89 Downloads / 264 Views

DOWNLOAD

REPORT


818 Susan Montgomery

Fixed Rings of Finite Automorphism Groups of Associative Rings

Springer-Verlag Berlin Heidelberg New York 1980

Author Susan Montgomery Department of Mathematics, University of Southern California Los Angeles, CA 90007/USA

AMS Subject Classifications (1980): 16-02, 16A08, 16A33, 16A34, 16A38, 16A72 ISBN 3-540-10232-9 Springer-Verlag Berlin Heidelberg NewYork ISBN 0-387-10232-9 Springer-Verlag NewYork Heidelberg Berlin This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photocopying machine or similar means, and storage in data banks. Under § 54 of the German Copyright Law where copies are made for other than private use, a fee is payable to the publisher, the amount of the fee to be determined by agreement with the publisher. © by Springer-Verlag Berlin Heidelberg 1980 Printed in Germany Printing and binding: Beltz Offsetdruck, Hemsbach/Bergstr. 2141/3140-543210

These notes

are d e d i c a t e d

Ora Beck German

to

PREFACE The first six chapters of these lecture notes are an expanded version of a series of seminar lectures, Southern California

begun at the University of

in the fall semester,

1976, continued at the

University of Chicago in the spring of 1977, the spring of 1978.

and completed at USC in

Chapter 7 includes some more recent results on

skew group rings and modules,

and provides

some alternate proofs of

material presented earlier. The intent of the lectures was to describe some of the many new results on fixed rings of automorphism groups which had been obtained since 1970; a g r e a t deal of progress had been made concerning the relationship of the structure of a ring R to the structure of a fixed subring R G with respect to a finite automorphism group G. to study this relationship, what circumstances teed.

In order

it was first necessary to know under

the existence of fixed elements

could be guaran-

We mention two papers which were fundamental to this problem:

the 1973 paper of G° Bergman and I.M. Isaacs, that if R is semiprime with no

IGI- torsion

order of G), then R G is non-trivial; V.K. Kharchenko,

in which they establish

(where

IGldenotes the

and the first 1975 paper of

in which he shows that if R has no nilpotent

elements and G is any finite group, is in this paper that Kharchenko

then R G is non-trivialo

Also,

it

introduces his notion of generalized

inner automorphisms. Once these results on the existence of R G were known, on chain conditions, became tractable,

polynomial

identities,

and R and R G - modules

in the situation when R had no

had no nilpotent elements, inner automorph-isms.

questions

IGI- torsion,

or R

or the group contained no "generalized"

These questions are the ones discussed here,

Vl along with the existence of trace functions

from R to RG and the rela-

tionship of R G to the skew group ring R*G.

These results occur in

work of M. Cohen, D.