272 citations · 424 across the 31 of their papers we have counts for
36 papers
Embeddability of higher-rank graphs in groupoids, and the structure of their C*-algebras
Nathan Brownlowe, Alex Kumjian, David Pask +1
We show that the C*-algebra of a row-finite source-free k-graph is Rieffel-Morita equivalent to a crossed product of an AF algebra by the fundamental group of the k-graph. When the…
Pushouts of extensions of groupoids by bundles of abelian groups
Marius Ionescu, Alex Kumjian, Jean N. Renault +2
We analyse extensions of groupoids by bundles of abelian groups. We describe a pushout construction for such extensions, and use it to describe the extension group of a…
Cocycles on Certain Groupoids Associated to -Actions
Carla Farsi, Leonard Huang, Alex Kumjian +1
We consider groupoids constructed from a finite number of commuting local homeomorphisms acting on a compact metric space, and study generalized Ruelle operators and -a…
C*-Algebras of extensions of groupoids by group bundles
Marius Ionescu, Alex Kumjian, Jean N. Renault +2
Given a normal subgroup bundle of the isotropy bundle of a groupoid , we obtain a twisted action of the quotient groupoid on the bundle of group $C^*…
Ample groupoids: equivalence, homology, and Matui's HK conjecture
Carla Farsi, Alex Kumjian, David Pask +1
We investigate the homology of ample Hausdorff groupoids. We establish that a number of notions of equivalence of groupoids appearing in the literature coincide for ample Hausdorff…
The Dixmier-Douady Classes of Certain Groupoid -Algebras with Continuous Trace
Marius Ionescu, Alex Kumjian, Aidan Sims +1
Given a locally compact abelian group , we give an explicit formula for the Dixmier--Douady invariant of the -algebra of the groupoid extension associated to a Čech -coc…