We give an upper bound for the number of conjugacy classes of closed subgroups of the full wreath product FWr W Sym which project onto Sym . Here, is infinite, W is the set of n-tuples of distinct elements from (for some finite n), F is a finite nilpotent group, and the topology on the wreath produc
The Noether Bound in Invariant Theory of Finite Groups
โ Scribed by Peter Fleischmann
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 133 KB
- Volume
- 156
- Category
- Article
- ISSN
- 0001-8708
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โฆ Synopsis
Let R be a commutative ring, V a finitely generated free R-module and G GL R (V) a finite group acting naturally on the graded symmetric algebra A=Sym(V). Let ;(A G ) denote the minimal number m, such that the ring A G of invariants can be generated by finitely many elements of degree at most m. Furthermore, let H dG be a normal subgroup such that the index |G : H | is invertible in R. In this paper we prove the inequality
For H=1 and |G | invertible in R we obtain Noether's bound ;(A G ) |G|, which so far had been shown for arbitrary groups only under the assumption that the factorial of the group order, |G|!, is invertible in R.
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