English

An Extension of Nori Fundamental Group

Algebraic Geometry 2021-08-25 v2

Abstract

In this paper, we study a certain extension of Nori's fundamental group in the case where a base field is of characteristic 0 and give structure theorems about it. As a result, for a smooth projective curve with genus gg>1, we prove that Nori's fundamental group acts faithfully on the category of unipotent bundles on the universal covering. In the case when g=1g=1, we give a more finer result.

Keywords

Cite

@article{arxiv.1508.04950,
  title  = {An Extension of Nori Fundamental Group},
  author = {Shusuke Otabe},
  journal= {arXiv preprint arXiv:1508.04950},
  year   = {2021}
}

Comments

30 pages, to appear in Comm Alg, Remark 1.6 is included, dropped the smoothness assumption from the most part, changed to use a word "unipotent bundle" instead of "nilpotent bundle", at a suggestion of the referee, Section 5.2 is included