K-Theory of Endomorphism Rings and of Rings of Invariants
✍ Scribed by Martin P Holland
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 269 KB
- Volume
- 191
- Category
- Article
- ISSN
- 0021-8693
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✦ Synopsis
This paper gives the following description of K of the endomorphism ring of a 0 finitely generated projective module.
THEOREM. Let T be a ring and P a finitely generated, projecti¨e T-module. Let I Ž . Ž . be the trace ideal of P. Then K End P is isomorphic to a subgroup of K T, I . If,
n phic to the subgroup of K T generated by the direct summands of P , for n g .ގ 0 As a corollary we can determine K of the ring of invariants for many free linear 0 actions. In particular, the following result is proved. THEOREM. Let V be a fixed-point-free linear representation of a finite group G o¨er Ž . a field k of characteristic zero and let S V be the symmetric algebra of V. Let K be any Ž Ž . G Ž .. ²w Ž . G Ž .x: finite-dimensional k-¨ector space. Then K S V m S K s S V m S K . 0 k k Ž . Similar results are given for suitable noncommutative versions of S V . ᮊ 1997
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