Fullness, Connes’ 𝜒-groups, and ultra-products of amalgamated free products over Cartan subalgebras

Ueda, Yoshimichi

doi:10.1090/S0002-9947-02-03100-8

Fullness, Connes’ $\chi$-groups, and ultra-products of amalgamated free products over Cartan subalgebras
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by Yoshimichi Ueda

Trans. Amer. Math. Soc. 355 (2003), 349-371

DOI: https://doi.org/10.1090/S0002-9947-02-03100-8

Published electronically: September 5, 2002

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Abstract:

Ultra-product algebras associated with amalgamated free products over Cartan subalgebras are investigated. As applications, their Connes’ $\chi$-groups are computed in terms of ergodic theory, and also we clarify what condition makes them full factors (i.e., their inner automorphism groups become closed).

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