Nori fundamental gerbe of essentially finite covers and Galois closure of towers of torsors

M. Antei; I. Biswas; M. Emsalem; F. Tonini; L. Zhang

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arXiv · 1706.00739

Nori fundamental gerbe of essentially finite covers and Galois closure of towers of torsors

M. Antei·I. Biswas·M. Emsalem·F. Tonini·L. Zhang

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Abstract

We prove the existence of a Galois closure for towers of torsors under finite group schemes over a proper, geometrically connected and geometrically reduced algebraic stack $X$ over a field $k$. This is done by describing the Nori fundamental gerbe of an essentially finite cover of $X$. A similar result is also obtained for the $S$-fundamental gerbe.

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BibTeX RIS

M. Antei, I. Biswas, M. Emsalem, F. Tonini, L. Zhang. 2017-06-02. Nori fundamental gerbe of essentially finite covers and Galois closure of towers of torsors. https://arxiv.org/abs/1706.00739

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