The coadjoint orbits for the series B , C , and D are considered in the case when the base point is a multiple of a fundamental weight. A quantization of the big cell is suggested by means of introducing a )-algebra generated by holomorphic coordinate functions. Starting from this algebraic structu
Invariant fields of symplectic and orthogonal groups
β Scribed by David J. Saltman
- Publisher
- Elsevier Science
- Year
- 2002
- Tongue
- English
- Weight
- 271 KB
- Volume
- 258
- Category
- Article
- ISSN
- 0021-8693
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β¦ Synopsis
The projective orthogonal and symplectic groups PO n (F ) and PSp n (F ) have a natural action on the F vector space
Here we assume F is an infinite field of characteristic not 2. If we assume there is more than one summand in V , then the invariant fields F (V ) PO n and F (V ) PSp n are natural objects. They are, for example, the centers of generic algebras with the appropriate kind of involution. This paper considers the rationality properties of these fields, in the case 1, 2, or 4 are the highest powers of 2 that divide n. We derive rationality when n is odd, or when 2 is the highest power, and stable rationality when 4 is the highest power. In a companion paper joint with Tignol, we prove retract rationality when 8 is the highest power of 2 dividing n. Back in this paper, along the way, we consider two generic ways of forcing a Brauer class to be in the image of restriction.
π SIMILAR VOLUMES
Markov chains are used to give a purely probabilistic way of understanding the conjugacy classes of the finite symplectic and orthogonal groups in odd characteristic. As a corollary of these methods, one obtains a probabilistic proof of Steinberg's count of unipotent matrices and generalizations of
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
Minimal sets of generators of the orthogonal groups on nonsingular quadratic spaces over a finite field are studied. All such orthogonal groups are shown to be generated by two elements, with the possible exception of two low-dimensional cases. 1994 Academic Press, Inc.