Good formal structures for flat meromorphic connections, I: Surfaces
Good formal structures for flat meromorphic connections, I: Surfaces
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平坦亚晶连接的良好形式结构,I:表面
DOI:
10.1215/00127094-2010-041
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发表时间:
2008
影响因子:
2.5
通讯作者:
K. Kedlaya
中科院分区:
文献类型:
--
作者:
K. Kedlaya
We give a criterion under which one can obtain a good decomposition (in the sense of Malgrange) of a formal flat connection on a complex analytic or algebraic variety of arbitrary dimension. The criterion is stated in terms of the spectral behavior of differential operators, and generalizes Robba's construction of the Hukuhara-Levelt-Turrittin decomposition in the one-dimensional case. As an application, we prove the existence of good formal structures for flat meromorphic connections on surfaces after suitable blowing up; this verifies a conjecture of Sabbah, and extends a result of Mochizuki for algebraic connections. Our proof uses a finiteness argument on the valuative tree associated to a point on a surface, in order to verify the numerical criterion.