An algorithm is presented which calculates rings of polynomial invariants of finite linear groups over an arbitrary field K. Up to now, such algorithms have been available only for the case that the characteristic of K does not divide the group order. Some applications to the question whether a modu
Invariants of Finite Groups over Fields of Characteristicp
β Scribed by David R. Richman
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 578 KB
- Volume
- 124
- Category
- Article
- ISSN
- 0001-8708
No coin nor oath required. For personal study only.
β¦ Synopsis
Let V denote a finite-dimensional K vector space and let G denote a finite group of K-linear automorphisms of V. Let V m denote the direct sum of m copies of V and let G act on the symmetric algebra K[V m ] of V m by the diagonal action on V m . A result of Noether implies that, if char K=0, then K[V m ] G can be generated as a K-algebra by polynomials whose degrees are |G|, no matter how large m is. This paper proves that this result no longer holds when the characteristic of K divides |G|. More precisely, it is proved in this case that there is a positive number :, depending only on |G| and char K, such that every set of K-algebra generators of K[V m ] G contains a generator whose degree is :m.
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