THE FUNDAMENTAL GROUP OF AN EXTENSION IN A TANNAKIAN CATEGORY AND THE UNIPOTENT RADICAL OF THE MUMFORD-TATE GROUP OF AN OPEN CURVE

被引:1
|
作者
Eskandari, Payman [1 ]
Murty, V. Kumar [2 ]
机构
[1] Univ Winnipeg, Dept Math & Stat, Winnipeg, MB, Canada
[2] Univ Toronto, Dept Math, Toronto, ON, Canada
关键词
Tannakian categories; Mumford-Tate groups; mixed Hodge structures; GALOIS GROUP;
D O I
10.2140/pjm.2023.325.255
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
In the first part, we give a self-contained account of Tannakian fundamental groups of extensions, generalizing a result of Hardouin (2008; 2011). In the second part, we use Hardouin's characterization of Tannakian groups of extensions to give a characterization of the unipotent radical of the Mumford- Tate group of an open complex curve. Consequently, we prove a formula that relates the dimension of the unipotent radical of the Mumford-Tate group of an open complex curve X \S with X smooth and projective and S a finite set of points to the rank of the subgroup of the Jacobian of X supported on S.
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页码:255 / 279
页数:28
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