De Finetti Theorem on the infinite non-commutative torus
Operator Algebras
2025-08-12 v1
Abstract
The set of spreadabl estates on an infinite non-commutive torus \mathbb{A}_{\mathbb{Z}_\alpha} is determined for all values of the deformation parameter {\alpha}. If {\alpha} is irrational, the canonical trace is the only spreadable 2{\pi} state. If {\alpha} is rational, the set of all spreadable states is a Bauer 2{\pi} simplex. Moreover, its boundary is the set of all infinite products of a single state on C(T). Finally, the simplex of all stationary states on \mathbb{A}_{\mathbb{Z}_\alpha} is proved to be the Poulsen simplex for all values of the deformation parameter {\alpha}.
Keywords
Cite
@article{arxiv.2508.08044,
title = {De Finetti Theorem on the infinite non-commutative torus},
author = {Vitonofrio Crismale and Simone Del Vecchio and Maria Elena Griseta and Stefano Rossi},
journal= {arXiv preprint arXiv:2508.08044},
year = {2025}
}