Abstract
We provide a close analysis of the connections between pseudogroups, groupoids, and toposes. This analysis provides a topos perspective on both the localic germ groupoid of a pseudogroup defined by Resende, and the topological groupoid of a pseudogroup defined by Lawson and Lenz. In particular, we show how to analyze the topos of a pseudogroup using sheaf theory, leading to an examination of pseudogroup torsors. Consequently we obtain a concrete description of the category of points of an étendue.
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Communicated by Mark V. Lawson.
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Funk, J., Hofstra, P. Pseudogroups and their torsors. Semigroup Forum 104, 281–319 (2022). https://doi.org/10.1007/s00233-022-10261-x
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DOI: https://doi.org/10.1007/s00233-022-10261-x