Exponential fields and Conway's omega-map

Abstract

Inspired by Conway's surreal numbers, we study real closed fields whose value group is isomorphic to the additive reduct of the field. We call such fields omega-fields and we prove that any omega-field of bounded Hahn series with real coefficients admits an exponential function making it into a model of the theory of the real exponential field. We also consider relative versions with more general coefficient fields.

15 pages; minor corrections and missing references; to appear in Proc. Amer. Math. Soc