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On the Fundamental Group of Type II$_1$ Factors

Sorin Popa
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Abstract

We present here a shorter version of the proof of a result from our paper ``On a class of type II$_1$ factors with Betti numbers invariants'', showing that the von Neumann factor associated with the group $\Bbb Z^2 \rtimes SL(2, \Bbb Z)$ has trivial fundamental group.

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Sorin Popa. 2002-10-30. On the Fundamental Group of Type II$_1$ Factors. https://arxiv.org/abs/math/0210467

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