Extensions of absolute values on two subfields
arXiv:2010.15641 · doi:10.1016/j.jalgebra.2022.01.016
Abstract
We describe the absolute values on a field which simultaneously extend absolute values on two subfields. We also give a common generalization of many versions of Abhyankar's lemma on ramification indices, which is both widely applicable and easy to state. We then apply these results to count points on the fibered product of two curve morphisms C --> X and D --> X which lie over prescribed points on C and D.
14 pages