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On purity of inertia

Author: David Harbater
Journal: Proc. Amer. Math. Soc. 112 (1991), 311-319
MSC: Primary 14E22; Secondary 12F12, 14G20, 14H30
MathSciNet review: 1064903
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Abstract: This paper considers the phenomenon of inertia groups jumping at regular points of the branch locus of a cover, especially in mixed characteristic. After giving conditions under which this cannot occur, these ideas are applied to the problem of obtaining groups as Galois groups of unramified covers of the affine line in finite characteristic.

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Keywords: Purity, inertia, branched cover, fundamental group
Article copyright: © Copyright 1991 American Mathematical Society