New York Journal of Mathematics
Volume 18 (2012) 797-834


Aviv Censor and Daniele Grandini

Weak pullbacks of topological groupoids

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Published: October 12, 2012
Keywords: Groupoid; Haar groupoid; Weak pullback; Haar system; quasi invariant measure; disintegration.
Subject: 22A22; 28A50

We introduce the category HG, whose objects are topological groupoids endowed with compatible measure theoretic data: a Haar system and a measure on the unit space. We then define and study the notion of weak pullback in the category of topological groupoids, and subsequently in HG. The category HG is the setting for topological groupoidification, which we present in separate papers, and in which the weak pullback is a key ingredient.

Author information

Aviv Censor:
Department of Mathematics, Technion - Israel Institute of Technology, Haifa 32000, Israel

Daniele Grandini:
Department of Mathematics and Statistics, University of New Mexico, Albuquerque, New Mexico 87131, USA