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arXiv · 2610.05990

Computable presentations of reduced group C*-algebras of groups with the rapid decay property

Isaac Goldbring
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Abstract

We show that whenever $G$ is a finitely generated group with the rapid decay property (property RD), then the norm on the reduced group C*-algebra $C^*_r(G)$ is computable if (and only if) $G$ has solvable word problem. We also give an example of a finitely presented group $G$ with solvable word problem for which the norm on $C^*_r(G)$ is not computable.

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Isaac Goldbring. 2026-10-05. Computable presentations of reduced group C*-algebras of groups with the rapid decay property. https://arxiv.org/abs/2610.05990

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