Let k be a field. A radical abelian algebra over k is a crossed product K/k Ξ± , where K = k T is a radical abelian extension of k, T is a subgroup of K \* which is finite modulo k \* , and Ξ± β H 2 G K \* is represented by a cocycle with values in T . The main result is that if A is a radical abelian
Exponent Reduction for Projective Schur Algebras
β Scribed by Eli Aljadeff; Jack Sonn
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 88 KB
- Volume
- 239
- Category
- Article
- ISSN
- 0021-8693
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β¦ Synopsis
In this paper it is proved that the ''exponent reduction property'' holds for all projective Schur algebras. This was proved in an earlier paper of the authors for a special class, the ''radical abelian algebras.'' The precise statement is as follows: let Ε½ . A be a projective Schur algebra over a field k and let k denote the maximal Ε½ . cyclotomic extension of k. If m is the exponent of A m k , then k contains a k primitive mth root of unity. One corollary of this result is a negative answer to the Ε½ . question of whether or not the projective Schur group PS k is always equal to Ε½ . Br Lrk , where L is the composite of the maximal cyclotomic extension of k and the maximal Kummer extension of k. A second consequence is a proof of the Ε½ . ''BrauerαWitt analogue'' in characteristic p: if char k s p / 0, then every projective Schur algebra over k is Brauer equivalent to a radical abelian algebra.
π SIMILAR VOLUMES
commutator is not trivial and therefore a primitive pth root of unity in k. Assume they commute. Then the algebra K they generate over k is
We prove a strong characteristic-free analogue of the classical adjoint formula s Ξ» s Β΅ f = s Ξ»/Β΅ f in the ring of symmetric functions. This is done by showing that the representative of a suitably chosen functor involving a tensor product is the skew Weyl module. By "strong" we mean that this repre
## Abstract To each irreducible infinite dimensional representation \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$(\pi ,\mathcal {H})$\end{document} of a __C__\*βalgebra \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\mathcal {A}$\end{doc