English

Generalization of Abhyankar's Lemma to henselian valued fields

Algebraic Geometry 2019-09-17 v1

Abstract

Abhyankar showed that for a finite tame extension L1/KL_1/K and a finite extension L2/KL_2/K of P\mathfrak{P}-adic fields, the condition [νL1:νK][\nu L_1 : \nu K] divides [νL2:νK][\nu L_2 : \nu K] is sufficient to eliminate ramification, that is, L1L2/L2L_1 \cdot L_2 / L_2 is unramified. In this paper, we show that the above condition is not sufficient in the case of an arbitrary henselian valued field. We construct a counterexample illustrating that fact. We also give a necessary and sufficient condition for the elimination of tame ramification of a henselian field after a finite extension of the base field.

Keywords

Cite

@article{arxiv.1909.06546,
  title  = {Generalization of Abhyankar's Lemma to henselian valued fields},
  author = {Arpan Dutta},
  journal= {arXiv preprint arXiv:1909.06546},
  year   = {2019}
}