An Extension of Nori Fundamental Group

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 $g$>1, we prove that Nori's fundamental group acts faithfully on the category of unipotent bundles on the universal covering. In the case when $g=1$, we give a more finer result.