Marius Ionescu

activity

20042022

most citedRemarks on the Ideal Structure of Fell Bundle C*-Algebras

13 citations · 28 across the 14 of their papers we have counts for

collaborators

19 papers

math.OA2022

Groupoid actions and Koopman representations

Valentin Deaconu, Marius Ionescu

We study the $C^{*}$ -algebra $C^{*} (κ)$ generated by the Koopman representation $κ = κ^{μ}$ of a locally compact groupoid $G$ acting on a measure space $(X, μ)$ , where $μ$ is quasi-invarian…

math.OA2021

Pushouts of extensions of groupoids by bundles of abelian groups

Marius Ionescu, Alex Kumjian, Jean N. Renault +2

We analyse extensions $Σ$ of groupoids $G$ by bundles $A$ of abelian groups. We describe a pushout construction for such extensions, and use it to describe the extension group of a…

math.OA2020

C*-Algebras of extensions of groupoids by group bundles

Marius Ionescu, Alex Kumjian, Jean N. Renault +2

Given a normal subgroup bundle $A$ of the isotropy bundle of a groupoid $Σ$ , we obtain a twisted action of the quotient groupoid $Σ/ A$ on the bundle of group $C^*…

math.OA2018

The Dixmier-Douady Classes of Certain Groupoid $C^{*}$ -Algebras with Continuous Trace

Marius Ionescu, Alex Kumjian, Aidan Sims +1

Given a locally compact abelian group $G$ , we give an explicit formula for the Dixmier--Douady invariant of the $C^{*}$ -algebra of the groupoid extension associated to a Čech $2$ -coc…

math.OA2016★ 1 cited

Obstructions to lifting cocycles on groupoids and the associated $C^{*}$ -algebras

Marius Ionescu, Alex Kumjian

Given a short exact sequence of locally compact abelian groups $0 \to A \to B \to C \to 0$ and a continuous $C$ -valued $1$ -cocycle $ϕ$ on a locally compact Hausdorff groupoid $Γ$ w…

math.OA2015

A Stabilization Theorem for Fell Bundles over groupoids