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A Galois Correspondence for Compact Groups of Automorphisms of von Neumann Algebras with a Generalization to Kac Algebras

✍ Scribed by Masaki Izumi; Roberto Longo; Sorin Popa


Publisher
Elsevier Science
Year
1998
Tongue
English
Weight
493 KB
Volume
155
Category
Article
ISSN
0022-1236

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✦ Synopsis


Let M be a factor with separable predual and G a compact group of automorphisms of M whose action is minimal, i.e., M G$ & M=C, where M G denotes the G-fixed point subalgebra. Then every intermediate von Neumann algebra M G /N/M has the form N=M H for some closed subgroup H of G. An extension of this result to the case of actions of compact Kac algebras on factors is also presented. No assumptions are made on the existence of a normal conditional expectation onto N.


πŸ“œ SIMILAR VOLUMES


Description of the Automorphism Group Au
✍ Takehiko Yamanouchi πŸ“‚ Article πŸ“… 2002 πŸ› Elsevier Science 🌐 English βš– 199 KB

It is shown that, for a minimal action a of a compact Kac algebra K on a factor A, the group of all automorphisms leaving the fixed-point algebra A a pointwise invariant is topologically isomorphic to the intrinsic group of the dual Kac algebra # K K. As an application, in the case where dim K o 1,