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比利时vs摩洛哥足彩 ,
university of california san diego

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seminar in operator algebras

ben hayes

vanderbilt university

weak equivalence to bernoulli shifts for some algebraic actions

abstract:

given two actions of a countable, discrete group $g$ on probabilty space $x,y$ there is a notion of when the action on $x$ is weakly contained in the action on $y$ (analogous to weak containment of representations) due to kechris: it roughly says that any finitary piece of the action of $g$ on $x$ can be approximated by some finitary piece of $g$ on $y$ (equivalent the measure on $x$ is a weak* limit of the factors of the measure on $y$). we then say that two actions are weakly equivalent when each is weakly contained in the other. we study when algebraic actions of $g$ (i.e. an action by automorphisms on a compact, metrizable, abelian group) are weakly equivalent to bernoulli shifts and find a natural class of actions related to invertible convolution operators on $g$. as part of our work, we also give conditions under which such actions are free.

host: adrian ioana

september 16, 2016

11:00 am

ap&m 5218

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