An isomorphism theorem for infinite reduced free products

Fuente: arXiv
Salvato in:
Dettagli Bibliografici
Autori principali: Hirshberg, Ilan, Phillips, N. Christopher
Natura: Preprint
Pubblicazione: 2026
Soggetti:
Accesso online:
Tags: Aggiungi Tag
Nessun Tag, puoi essere il primo ad aggiungerne!!
_version_ 1866915790367752192
author Hirshberg, Ilan
Phillips, N. Christopher
author_facet Hirshberg, Ilan
Phillips, N. Christopher
contents Let C be a separable unital C*-algebra, not isomorphic to the complex numbers, equipped with a faithful tracial state. Let A be a unital direct limit of one dimensional NCCW complexes, also equipped with a faithful tracial state. Suppose there is a unital trace preserving embedding of A in the Jiang-Su algebra which is an isomorphism on K-theory. (For example, A could be C([0,1]) with Lebesgue measure, or the Jiang-Su algebra itself.) Let D be the infinite reduced free product of copies of C. Then the reduced free product A*D is isomorphic to D. If D has real rank zero and C is exact, then in place of A we can use C(X) for any contractible compact metric space X and any faithful tracial state on C(X). An example consequence is that the reduced free product of infinitely many copies of C([0, 1]), with Lebesgue measure, is isomorphic to the reduced free product of infinitely many copies of the Jiang-Su algebra.
format Preprint
id arxiv_https___arxiv_org_abs_2602_10220
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle An isomorphism theorem for infinite reduced free products
Hirshberg, Ilan
Phillips, N. Christopher
Operator Algebras
46L09
Let C be a separable unital C*-algebra, not isomorphic to the complex numbers, equipped with a faithful tracial state. Let A be a unital direct limit of one dimensional NCCW complexes, also equipped with a faithful tracial state. Suppose there is a unital trace preserving embedding of A in the Jiang-Su algebra which is an isomorphism on K-theory. (For example, A could be C([0,1]) with Lebesgue measure, or the Jiang-Su algebra itself.) Let D be the infinite reduced free product of copies of C. Then the reduced free product A*D is isomorphic to D. If D has real rank zero and C is exact, then in place of A we can use C(X) for any contractible compact metric space X and any faithful tracial state on C(X). An example consequence is that the reduced free product of infinitely many copies of C([0, 1]), with Lebesgue measure, is isomorphic to the reduced free product of infinitely many copies of the Jiang-Su algebra.
title An isomorphism theorem for infinite reduced free products
topic Operator Algebras
46L09
url https://arxiv.org/abs/2602.10220