Formal deformations of wildly ramified cover
成果类型：
Article
署名作者：
Bertin, J; Mézard, A
署名单位：
Communaute Universite Grenoble Alpes; Universite Grenoble Alpes (UGA)
刊物名称：
INVENTIONES MATHEMATICAE
ISSN/ISSBN：
0020-9910
DOI：
10.1007/s002220000071
发表日期：
2000
页码：
195-238
关键词：
摘要：
In this paper we study formal moduli for wildly ramified Galois covering. We prove a local-global principle. We then focus on the infinitesimal deformations of the Z/pZ-covers. We explicitly compute a deformation of an automorphism of order p which implies a universal obstruction for p > 2. By deforming Artin-Schreier equations we obtain a lower bound on the dimension of the local versal deformation ring. At last, by comparing the global versal deformation ring to the complete local ring in a point of a moduli space, we determine the dimensions of the global and local versal deformation rings.