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2010 The classifying topos of a topological bicategory
Igor Baković, Branislav Jurčo
Homology Homotopy Appl. 12(1): 279-300 (2010).


For any topological bicategory $\mathbb{B}$, the Duskin nerve $N\mathbb{B}$ of $B$ is a simplicial space. We introduce the classifying topos $\mathcal{B}\mathbb{B}$ of $\mathbb{B}$ as the Deligne topos of sheaves Sh$(N\mathbb{B})$ on the simplicial space $N\mathbb{B}$. It is shown that the category of geometric morphisms Hom(Sh($X), \mathcal{B}\mathbb{B}$) from the topos of sheaves Sh($X$) on a topological space $X$ to the Deligne classifying topos is naturally equivalent to the category of principal $\mathbb{B}$-bundles. As a simple consequence, the geometric realization $|N\mathbb{B}|$ of the nerve $N\mathbb{B}$ of a locally contractible topological bicategory $\mathbb{B}$ is the classifying space of principal $\mathbb{B}$-bundles, giving a variant of the result of Baas, Bökstedt and Kro derived in the context of bicategorical $K$-theory. We also define classifying topoi of a topological bicategory $\mathbb{B}$ using sheaves on other types of nerves of a bicategory given by Lack and Paoli, Simpson and Tamsamani by means of bisimplicial spaces, and we examine their properties.


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Igor Baković. Branislav Jurčo. "The classifying topos of a topological bicategory." Homology Homotopy Appl. 12 (1) 279 - 300, 2010.


Published: 2010
First available in Project Euclid: 28 January 2011

zbMATH: 1278.18004
MathSciNet: MR2638874

Primary: 18D05, 18F20, 55U40

Rights: Copyright © 2010 International Press of Boston


Vol.12 • No. 1 • 2010
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