Topological full groups of ultragraph groupoids as an isomorphism invariant

GG de Castro, D Gonçalves, DW van Wyk - arXiv preprint arXiv …, 2019 - arxiv.org
We prove two isomorphism-invariance theorems for groupoids associated with ultragraphs.
These theorems characterize ultragraphs for which the topological full group of an …

Groupoids and Hermitian Banach*-algebras

A Austad, E Ortega - International Journal of Mathematics, 2022 - World Scientific
We study when the twisted groupoid Banach*-algebra L 1 (𝒢, σ) is Hermitian. In particular,
we prove that Hermitian groupoids satisfy the weak containment property. Furthermore, we …

Studying Stein's Groups as Topological Full Groups

O Tanner - arXiv preprint arXiv:2312.07375, 2023 - arxiv.org
We include a class of generalisations of Thompson's group $ V $ introduced by Melanie
Stein into the growing framework of topological full groups. Like $ V $, Stein's groups can be …

Shadowing, finite order shifts and ultrametric spaces

UB Darji, D Gonçalves, M Sobottka - Advances in Mathematics, 2021 - Elsevier
Inspired by a recent novel work of Good and Meddaugh, we establish fundamental
connections between shadowing, finite order shifts, and ultrametric complete spaces. We …

Generalisations of Thompson's group V arising from purely infinite groupoids

E Gardella, O Tanner - arXiv preprint arXiv:2302.04078, 2023 - arxiv.org
We study a class of generalisations of Thompson's group $ V $ arising naturally as
topological full groups of purely infinite, minimal groupoids. In the process, we show that the …

KMS states and continuous orbit equivalence for ultragraph shift spaces with sinks

FA Tasca, D Gonçalves - Publicacions matematiques, 2022 - projecteuclid.org
We extend ultragraph shift spaces and the realization of ultragraph C*-algebras as partial
crossed products to include ultragraphs with sinks (under a mild condition, called (RFUM2) …

Matui's AH conjecture for Graph Groupoids

P Nyland, E Ortega - Documenta Mathematica, 2021 - ems.press
We prove that Matui's AH conjecture holds for graph groupoids of infinite graphs. This is a
conjecture which relates the topological full group of an ample groupoid with the homology …

Boundary maps, germs and quasi-regular representations

M Kalantar, E Scarparo - Advances in Mathematics, 2022 - Elsevier
We investigate the tracial and ideal structures of C⁎-algebras of quasi-regular
representations of stabilizers of boundary actions. Our main tool is the notion of boundary …

Banach algebras associated to twisted\'{e} tale groupoids: simplicity and pure infiniteness

K Bardadyn, B Kwaśniewski, A McKee - arXiv preprint arXiv:2406.05717, 2024 - arxiv.org
We define reduced and essential Banach algebras associated to a twisted\'{e} tale (not
necessarily Hausdorff) groupoid $(\mathcal {G},\mathcal {L}) $ and extend some …

The groupoids of adaptable separated graphs and their type semigroups

P Ara, J Bosa, E Pardo, A Sims - … Mathematics Research Notices, 2021 - academic.oup.com
Given an adaptable separated graph, we construct an associated groupoid and explore its
type semigroup. Specifically, we first attach to each adaptable separated graph a …