Brix, K. A., Carlsen, T. M. and Sims, A. (2024) Some results regarding the ideal structure of C*-algebras of étale groupoids. Journal of the London Mathematical Society, 109(3), e12870. (doi: 10.1112/jlms.12870)
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Abstract
We prove a sandwiching lemma for inner-exact locally compact Hausdorff étale groupoids. Our lemma says that every ideal of the reduced C*-algebra of such a groupoid is sandwiched between the ideals associated to two uniquely defined open invariant subsets of the unit space. We obtain a bijection between ideals of the reduced C*-algebra, and triples consisting of two nested open invariant sets and an ideal in the C*-algebra of the subquotient they determine that has trivial intersection with the diagonal subalgebra and full support. We then introduce a generalisation to groupoids of Ara and Lolk's relative strong topological freeness condition for partial actions, and prove that the reduced C*-algebras of inner-exact locally compact Hausdorff étale groupoids satisfying this condition admit an obstruction ideal in Ara and Lolk's sense.
Item Type: | Articles |
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Additional Information: | This research was supported by Australian Research Council grant DP200100155. KAB acknowledges the support of the Carlsberg Foundation via an Internationalisation Fellowship and the support of the Independent Research Fund Denmark (Case number 1025-00004B). |
Status: | Published |
Refereed: | Yes |
Glasgow Author(s) Enlighten ID: | Brix, Dr Kevin |
Authors: | Brix, K. A., Carlsen, T. M., and Sims, A. |
College/School: | College of Science and Engineering > School of Mathematics and Statistics > Mathematics |
Journal Name: | Journal of the London Mathematical Society |
Publisher: | Wiley |
ISSN: | 0024-6107 |
ISSN (Online): | 1469-7750 |
Published Online: | 20 February 2024 |
Copyright Holders: | Copyright © 2024 The Authors |
First Published: | First published in Journal of the London Mathematical Society 109(3):e12870 |
Publisher Policy: | Reproduced under a Creative Commons licence |
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