Computable $K$-theory for C*-algebras II: AF algebras

Fuente: arXiv
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Auteurs principaux: Eagle, Christopher J., Goldbring, Isaac, McNicholl, Timothy H.
Format: Preprint
Publié: 2026
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author Eagle, Christopher J.
Goldbring, Isaac
McNicholl, Timothy H.
author_facet Eagle, Christopher J.
Goldbring, Isaac
McNicholl, Timothy H.
contents We continue the study of the effective content of $K$-theory for C*-algebras, with a focus on AF algebras. We show that from a c.e. presentation of an AF algebra it is possible to compute a representation of the algebra as an inductive limit of finite-dimensional algebras. Using this, and an analogous result for dimension groups, we show that the computable $K_0$ functor provides a computable equivalence of categories between c.e. presentations of AF algebras and c.e. presentations of unital (scaled) dimension groups, giving an effective version of Elliott's classification theorem. We use our results to determine the complexity of the index set and isomorphism problems for various classes of AF algebras.
format Preprint
id arxiv_https___arxiv_org_abs_2602_06882
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Computable $K$-theory for C*-algebras II: AF algebras
Eagle, Christopher J.
Goldbring, Isaac
McNicholl, Timothy H.
Operator Algebras
Logic
We continue the study of the effective content of $K$-theory for C*-algebras, with a focus on AF algebras. We show that from a c.e. presentation of an AF algebra it is possible to compute a representation of the algebra as an inductive limit of finite-dimensional algebras. Using this, and an analogous result for dimension groups, we show that the computable $K_0$ functor provides a computable equivalence of categories between c.e. presentations of AF algebras and c.e. presentations of unital (scaled) dimension groups, giving an effective version of Elliott's classification theorem. We use our results to determine the complexity of the index set and isomorphism problems for various classes of AF algebras.
title Computable $K$-theory for C*-algebras II: AF algebras
topic Operator Algebras
Logic
url https://arxiv.org/abs/2602.06882