# The Dixmier-Douady classes of certain groupoid C∗-algebras with continuous trace

@article{Ionescu2018TheDC, title={The Dixmier-Douady classes of certain groupoid C∗-algebras with continuous trace}, author={Marius Ionescu and Alex Kumjian and Aidan Sims and Dana P. Williams}, journal={Journal of Operator Theory}, year={2018} }

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 Cech 2-cocycle in the sheaf of germs of continuous G-valued functions. We then exploit the blow-up construction for groupoids to extend this to some more general central extensions of etale equivalence relations.

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