Solution of the factorial Stone-Weierstrass conjecture. An application of the theory of standard splitW*-inclusions
Solution of the factorial Stone-Weierstrass conjecture. An application of the theory of standard splitW*-inclusions
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阶乘 Stone-Weierstrass 猜想的解。
DOI:
10.1007/bf01388497
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发表时间:
1984
影响因子:
3.1
通讯作者:
R. Longo
中科院分区:
文献类型:
--
作者:
R. Longo
The main result in this paper is the positive solution of a long-standing problem in Operator Algebras, namely the existence, in any factor M with separable predual, of an AFD (Approximately Finite Dimensional) subfactor R which is singular in M, ie R'A M= C 1. This result, which is closely related to some of the RV Kadison's Baton Rouge Problems [10], has been obtained by S. Popa [16] in case M is a II-factor, while we deal with infinite factors. The relevance of our result is better understood by its major implications, which have been recognized through the years (and need the result only for infinite factors). The positive solution of two classical problems in C*-algebra theory (see [19, final remarks]) will follow indeed. The first application shows that, given two C*-algebras A c B with A separable, any factor state q5 of A extends to a factor state of B. Indeed an old argument of S. Sakai [20], see [5, 12], proves the result if A is nuclear or, more generally, if 7~(A)'contains a singular injective subfactor. The second implication is the positive solution of the weak Stone-Weierstrass Conjecture, namely if A c B are separable C*-algebras and A separates the factor states of B, then A= B. Indeed Anderson and Bunce [-3](see also [15]) have shown that this follows by the result we are now proving. We refer to [2, 4, 8, 9, 11, 18] for the earlier developments on a non commutative Stone-Weierstrass theorem.