Let F be an arbitrary field and let D be a division algebra having center F which is finite dimensional over F. In general, there need not exist a maximal subfield E of D which is Galois over F. If such an E exists, we Ε½ call D a crossed product or G G-crossed product if G G is the Galois group of .
Division Algebras Not Embeddable in Crossed Products
β Scribed by Eric S. Brussel
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 317 KB
- Volume
- 179
- Category
- Article
- ISSN
- 0021-8693
No coin nor oath required. For personal study only.
β¦ Synopsis
We show that division algebras do not always embed in crossed product division algebras, so the latter do not serve as ''Galois closures'' for division algebras. We construct decomposable noncrossed product division algebras of prime-power index over rational function fields and Laurent series fields over number fields. We discover a rigid nonabelian group of order p 4 .
π SIMILAR VOLUMES
We investigate the problem of explicitly constructing non-cyclic free groups in finite-dimensional crossed products using valuation criteria. The results are applied to produce explicit free groups in division algebras generated by nilpotent groups, and symmetric free groups in group rings of finite
We will show that the crossed products of unital simple real rank zero AT algebras by the integers are AF embeddable. This is a generalization of Brown's AF embedding theorem. As an application, we will prove the AF embeddability of crossed product algebras arising from certain minimal dynamical sys