Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-24T01:56:27.750Z Has data issue: false hasContentIssue false

The Asymptotic Ratio Set and Direct Integral Decompositions of a Von Neumann Algebra

Published online by Cambridge University Press:  20 November 2018

Ole A. Nielsen*
Affiliation:
Queen's University, Kingston, Ontario
Rights & Permissions [Opens in a new window]

Extract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The fact that any von Neumann algebra on a separable Hilbert space has an essentially unique direct integral decomposition into factors means that there is a global as well as a local aspect to any partial classification of von Neumann algebras. More precisely, suppose that J is a statement about von Neumann algebras which is either true or false for any given von Neumann algebra. Then a von Neumann algebra is said to satisfy J globally if it satisfies J, and to satsify J locally if almost all the factors appearing in some (and hence in any) central decomposition of it satisfy J . In a recent paper [3], H. Araki and E. J. Woods introduced the notion of the asymptotic ratio set of a factor, and by means of this they made remarkable progress in the classification of factors.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1971

References

1. Araki, H., A classification of factors. II, Publ. Res. Inst. Math. Sci. Ser. A. 4 (1968), 585593.Google Scholar
2. Araki, H., Asymptotic ratio set and property Lλ', Publ. Res. Inst. Math. Sci. Ser. A 6 (1971), 443460.Google Scholar
3. Araki, H. and Woods, E. J., A classification of factors, Publ. Res. Inst. Math. Sci. Ser. A. 4 (1968), 51130.Google Scholar
4. Auslander, L. and Moore, C. C., Unitary representations of solvable Lie groups, Mem. Amer. Math. Soc. No. 62 (Amer. Math. Soc, Providence, 1966).Google Scholar
5. Dixmier, J., Les algebres oVopérateurs dans l'espace Hilbertien, second edition (Gauthier-Villars, Paris, 1969).Google Scholar
6. Effros, E. G., The Borel space of von Neumann algebras on a separable Hilbert space, Pacific J. Math. 15 (1965), 11531164.Google Scholar
7. Effros, E. G., Global structure in von Neumann algebras, Trans. Amer. Math. Soc. 121 (1966), 434454.Google Scholar
8. Guichardet, A., Une caratérisation des algebres de von Neumann discrètes, Bull. Soc. Math. France 89 (1961), 77101.Google Scholar
9. Mackey, G. W., Borel structures in groups and their duals, Trans. Amer. Math. Soc. 85 (1957), 134165.Google Scholar
10. Nielsen, O. A., New proofs of Sakai's theorems on global von Neumann algebras (to appear).Google Scholar
11. Powers, R. T., Representations of uniformly hyper finite algebras and their associated von Neumann rings, Ann. of Math. 86 (1967), 138171.Google Scholar
12. Schwartz, J. T., W*-Algebras (Gordon and Breach, New York, 1967).Google Scholar