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arXiv · 1404.3830

Essential commutants of semicrossed products

Kei Hasegawa
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Abstract

Let $α:G \curvearrowright M$ be a spatial action of countable abelian group on a "spatial" von Neumann algebra $M$ and $S$ be its unital subsemigroup with $G=S^{-1}S$. We explicitly compute the essential commutant and the essential fixed-points, modulo the Schatten $p$-class or the compact operators, of the w$^*$-semicrossed product of $M$ by $S$ when $M'$ contains no non-zero compact operators. We also prove a weaker result when $M$ is a von Neumann algebra on a finite dimensional Hilbert space and $(G,S)=(\mathbb{Z},\mathbb{Z}_{+})$, which extends a famous result due to Davidson (1977) for the classical analytic Toeplitz operators.

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Kei Hasegawa. 2014-04-15. Essential commutants of semicrossed products. https://doi.org/10.4153/cmb-2014-057-x

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