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Groupoid strict comparison for Ample Groupoids: Fiberwise Supramenability and Topological Amenability
Abstract
In this paper, we first introduce fiberwise supramenability for locally compact Hausdorff étale groupoids with compact unit space. Then, for such a minimal ample groupoid 𝒢, we show that if 𝒢 is fiberwise supramenable or topologically amenable, then the clopen type semigroup S(𝒢) is almost unperforated. Consequently, if 𝒢 is σ-compact, then it has groupoid strict comparison. We then present several applications, including Matui's AH conjecture and pure infiniteness for groupoids and groupoid C*-algebras.
Related
BibTeX
@misc{liu2026groupoid,
title = {{Groupoid strict comparison for Ample Groupoids: Fiberwise Supramenability and Topological Amenability}},
author = {Chunlin Liu and Xin Ma and Jianchao Wu},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.08511},
eprint = {2610.08511},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.08511},
}
RIS
TY - UNPB
TI - Groupoid strict comparison for Ample Groupoids: Fiberwise Supramenability and Topological Amenability
AU - Chunlin Liu
AU - Xin Ma
AU - Jianchao Wu
PY - 2026
DA - 2026/10/06
PB - arXiv
DO - 10.48550/arxiv.2610.08511
UR - https://arxiv.org/abs/2610.08511
AB - In this paper, we first introduce fiberwise supramenability for locally compact Hausdorff étale groupoids with compact unit space. Then, for such a minimal ample groupoid 𝒢, we show that if 𝒢 is fiberwise supramenable or topologically amenable, then the clopen type semigroup S(𝒢) is almost unperforated. Consequently, if 𝒢 is σ-compact, then it has groupoid strict comparison. We then present several applications, including Matui's AH conjecture and pure infiniteness for groupoids and groupoid C^*-algebras.
ER -