PreprintCC BY 4.0arXiv
1-Bounded Entropy for C*-Algebras
Abstract
Towards a question of Voiculescu, two notions of $1$-bounded entropy, h and htop, are defined for C*-algebras. The quantity h involves the tracial completion with respect to all traces while the quantity htop depends on operator norm microstates. It is demonstrated that htop(π) does not exceed h(π) for all C*-algebras π. Moreover, a variational principle enabling the computation of h is introduced. The quantity h is computed in various examples, and the computation is used to justify structural conclusions such as C*-primeness, crossed product indecomposability, and free indecomposability. These notions of entropy are generalized to operator systems, where it is demonstrated that both may be computed on a basis.
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BibTeX
@misc{macmahon20261bounded,
title = {{1-Bounded Entropy for $C^*$-Algebras}},
author = {Connor MacMahon},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.15409},
eprint = {2608.15409},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.15409},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - 1-Bounded Entropy for C^*-Algebras
AU - Connor MacMahon
PY - 2026
DA - 2026/08/31
PB - arXiv
DO - 10.48550/arxiv.2608.15409
UR - https://arxiv.org/abs/2608.15409
AB - Towards a question of Voiculescu, two notions of $1$-bounded entropy, h and h^top, are defined for C^*-algebras. The quantity h involves the tracial completion with respect to all traces while the quantity h^top depends on operator norm microstates. It is demonstrated that h^top(π) does not exceed h(π) for all C^*-algebras π. Moreover, a variational principle enabling the computation of h is introduced. The quantity h is computed in various examples, and the computation is used to justify structural conclusions such as C^*-primeness, crossed product indecomposability, and free indecomposability. These notions of entropy are generalized to operator systems, where it is demonstrated that both may be computed on a basis.
ER -