Analytic Ax-Kochen-Ersov theory with lifts of the residue field and value group

Abstract

We develop an extension theory for analytic valuation rings in order to establish Ax-Kochen-Ersov (AKE) type results for these structures. New is that we can add in salient cases lifts of the residue field and the value group and show that the induced structure on the lifted residue field is just its field structure, and on the lifted value group is just its ordered abelian group structure. This restores an analogy with the nonanalytic AKE-setting that was missing in earlier treatments of analytic AKE-theory.