English

On quasi-purity of the branch locus

Algebraic Geometry 2020-09-08 v2 Number Theory

Abstract

Let kk be a field, K/kK/k finitely generated and L/KL/K a finite, separable extension. We show that the existence of a kk-valuation on LL which ramifies in L/KL/K implies the existence of a normal model XX of KK and a prime divisor DD on the normalization XLX_L of XX in LL which ramifies in the scheme morphism XLXX_L \rightarrow X. Assuming the existence of a regular, proper model XX of KK, this is a straight-forward consequence of the Zariski-Nagata theorem on the purity of the branch locus. We avoid assumptions on resolution of singularities by using M. Temkin's inseparable local uniformization theorem.

Keywords

Cite

@article{arxiv.1807.07748,
  title  = {On quasi-purity of the branch locus},
  author = {Alexander Schmidt},
  journal= {arXiv preprint arXiv:1807.07748},
  year   = {2020}
}

Comments

Weakened the assumptions of Theorem B