Unbounded expectations to some von Neumann algebras

Erik Christensen

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arXiv · 2005.13226

Unbounded expectations to some von Neumann algebras

Erik Christensen

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Abstract

For any injective von Neumann algebra R and any discrete, countable group G, which acts by *-automorphisms on R, we construct an idempotent mapping of an ultra-weakly dense subspace of B(H) onto the reducerd crossed product von Neumann algebra, such that it is R-bimodular and satisfies some nice relations with respect to positivity. In the case of an amenable group our unbounded expectation turns into a usual conditional expectation of norm 1.

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Erik Christensen. 2020-05-27. Unbounded expectations to some von Neumann algebras. https://arxiv.org/abs/2005.13226

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