Bull. Austral. Math. Soc. 72(2) pp.317--324, 2005.
Complementation of the Jacobson group in a matrix ring
David Dolžan |
.
Abstract
The Jacobson group of a ring R (denoted by = (R)) is the normal subgroup of the group of
units of R (denoted by
G(R)) obtained by adding 1
to the Jacobson radical of R
J(R).
Coleman and Easdown in 2000 showed that the Jacobson group is
complemented in the group of units of any finite commutative ring
and also in the group of units of a n×n matrix ring over integers modulo
ps, when
n = 2 and p = 2, 3, but it is not complemented when
p5. In 2004
Wilcox showed that the answer is positive also for n = 3 and p =
2, and negative in all the remaining cases. In this paper we
offer a different proof for Wilcox's results and also generalise
the results to a matrix ring over an arbitrary finite commutative
ring. We show this by studying the generators and relations that
define a matrix ring over a field. We then proceed to examine the
complementation of the Jacobson group in the matrix rings over
graded rings and prove that complementation depends only on the
0-th grade.
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[an error occurred while processing this directive](Metadata: XML, RSS, BibTeX) | MathSciNet: MR2183412 | Z'blatt-MATH: 02246393 |
References
- C. Coleman and D. Easdown;
Complementtionin the group of units of a ring,
Bull. Austral. Math. Socl. 62 (2000), pp. 183--192. MR1786200 - M. Hall;
The theory of groups (Macmillan, New York, 1959). MR103215 - G. Karpilovsky;
Group representations, Vol 1 (Elsevier Science Publishers B.V., Amsterdam, 1992). MR1183469 - B.R. McDonald;
Finite rings with identity (Marcel Dekker Inc., New York). MR354768 - R. Raghavendran;
Finite associative rings,
Compositio Math. 21 (1969), pp. 195--229. MR246905 - J.J. Rotman;
The theory of groups, an introduction (Allyn and Bacon, Inc., Boston, 1973). MR0442063, MR0690593 - S. Wilcox;
Complementation in the group of units of matrix rings,
Bull. Austral. Math. Soc. 70 (2004), pp. 223-227. MR2094290
ISSN 0004-9727