DISTALITY IN VALUED FIELDS AND RELATED STRUCTURES

We investigate distality and existence of distal expansions in val-ued fields and related structures. In particular, we characterize distality in a large class of ordered abelian groups, provide an Ax-Kochen-Ers??ov-style char-acterization for henselian valued fields, and demonstrate that certain expan-sions of fields, e.g., the differential field of logarithmic-exponential transseries, are distal. As a new tool for analyzing valued fields we employ a relative quantifier elimination for pure short exact sequences of abelian groups.