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arXiv · 1511.00307

Approximate equivalence of actions

Andreas Aaserud·Sorin Popa
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Abstract

We consider several weaker versions of the notion of conjugacy and orbit equivalence of measure preserving actions of countable groups on probability spaces, involving equivalence of the ultrapower actions and asymptotic intertwining conditions. We compare them with the other existing equivalence relations between group actions, and study the usual type of rigidity questions around these new concepts (superrigidity, calculation of invariants, etc).

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Andreas Aaserud, Sorin Popa. 2015-11-01. Approximate equivalence of actions. https://arxiv.org/abs/1511.00307

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