Differentially Henselian Fields

Abstract

We study the class of differentially henselian fields, which are henselian valued fields equipped with generic derivations in the sense of Cubides Kovacics and Point, and are special cases of differentially large fields in the sense of Le\'on S\'anchez and Tressl. We prove that many results from henselian valued fields as well as differentially large fields can be lifted to the differentially henselian setting, for instance Ax-Kochen/Ershov principles, characterisations in terms of differential algebras, etc. We also give methods to concretely construct such fields in terms of iterated power series expansions and inductive constructions on transcendence bases.