Toroidal Resolutions for Some Matrix Singularities
Toroidal Resolutions for Some Matrix Singularities
复制标题
某些矩阵奇点的环形分辨率
DOI:
10.1007/978-3-0348-8303-0_5
复制
发表时间:
2001
影响因子:
0.9
通讯作者:
G. Faltings
中科院分区:
文献类型:
--
作者:
G. Faltings
In the classical theory of modular curves parametrising abelian varieties with level structures an important role is played by Drinfeld level structures. These allow us to find reasonably good models over primes of bad characteristics, see for example the book [KM] by Katz and Mazur. Unfortunately we have no such device for abelian varieties of higher dimensions. As a modest replacement one can use explicit equations for the relevant singularities. These are given by identities between matrices, but they cover only the case where the level is divisible by the characteristicpbut not by its square. Here the pioneers are Chai/Norman and Deligne/Pappas ([CN], [DP]). In a previous paper [F] I had constructed explicit resolutions for such singularities which are associated to symmetric spaces. Here we extend this (in some cases) to the level structures associated to an Iwahori subgroup, which seems to be the maximum possible accessible by these methods. However we can only show that our models have toroidal singularities.