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arXiv · 2607.03129

A C*-diagonal in the Jiang-Su algebra via entangled matrix cones

Lukas Obermeyer·Wilhelm Winter
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Abstract

We construct the Jiang-Su algebra Z as an inductive limit of dimension drop algebras, describing the latter as entangled matrix cones to explicitly define the connecting *-homomorphisms. This construction gives rise to a C*-diagonal in Z with one-dimensional spectrum which is not locally connected. Along the way, we give a new characterisation of normalisers in Cartan pairs in terms of state excision.

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Lukas Obermeyer, Wilhelm Winter. 2026-07-03. A C*-diagonal in the Jiang-Su algebra via entangled matrix cones. https://arxiv.org/abs/2607.03129

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