MODEL THEORY OF DIFFERENTIAL-HENSELIAN PRE- <i>H</i> -FIELDS

Abstract Pre- H -fields are ordered valued differential fields satisfying some basic axioms coming from transseries and Hardy fields. We study pre- H -fields that are differential-Hensel–Liouville closed, that is, differential-henselian, real closed, and closed under exponential integration, establishing an Ax–Kochen/Ershov theorem for such structures: the theory of a differential-Hensel–Liouville closed pre- H -field is determined by the theory of its ordered differential residue field; this result fails if the assumption of closure under exponential integration is dropped. In a two-sorted setting with one sort for a differential-Hensel–Liouville closed pre- H -field and one sort for its ordered differential residue field, we eliminate quantifiers from the pre- H -field sort, from which we deduce that the ordered differential residue field is purely stably embedded and if it has NIP, then so does the two-sorted structure. Similarly, the one-sorted theory of differential-Hensel–Liouville closed pre- H -fields with closed ordered differential residue field has quantifier elimination, is the model completion of the theory of pre- H -fields with gap $0$ , and is complete, distal, and locally o-minimal.