Free products with amalgamation over central $\mathrm {C}^*$-subalgebras
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- by Kristin Courtney and Tatiana Shulman PDF
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Abstract:
Let $A$ and $B$ be $\mathrm {C}^*$-algebras whose quotients are all RFD (residually finite dimensional), and let $C$ be a central $\mathrm {C}^*$-subalgebra in both $A$ and $B$. We prove that the full amalgamated free product $A*_C B$ is then RFD. This generalizes Korchagin’s result that amalgamated free products of commutative $\mathrm {C}^*$-algebras are RFD. When applied to the case of trivial amalgam, our methods recover the result of Exel and Loring for separable $\mathrm {C}^*$-algebras. As corollaries to our theorem, we give sufficient conditions for amalgamated free products of maximally almost periodic (MAP) groups to have RFD $\mathrm {C}^*$-algebras and hence to be MAP.References
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Additional Information
- Kristin Courtney
- Affiliation: Mathematical Institute, WWU Münster, Einsteinstr. 62, Münster, Germany
- MR Author ID: 1314625
- Email: kcourtne@uni-muenster.de
- Tatiana Shulman
- Affiliation: Department of Mathematical Physics and Differential Geometry, Institute of Mathematics of Polish Academy of Sciences, Warsaw, Poland
- MR Author ID: 684365
- Email: tshulman@impan.pl
- Received by editor(s): December 14, 2018
- Received by editor(s) in revised form: June 8, 2019
- Published electronically: September 20, 2019
- Additional Notes: The research of the first-named author was supported by the Deutsche Forschungsgemeinschaft (SFB 878 Groups, Geometry & Actions).
The research of the second-named author was supported by the Polish National Science Centre grant under the contract number DEC- 2012/06/A/ST1/00256, by the grant H2020-MSCA-RISE-2015-691246-QUANTUM DYNAMICS and Polish Government grant 3542/H2020/2016/2, and from the Eric Nordgren Research Fellowship Fund at the University of New Hampshire. - Communicated by: Adrian Ioana
- © Copyright 2019 American Mathematical Society
- Journal: Proc. Amer. Math. Soc. 148 (2020), 765-776
- MSC (2010): Primary 46L05; Secondary 47A67
- DOI: https://doi.org/10.1090/proc/14746
- MathSciNet review: 4052213