Surreal ordered exponential fields
Abstract
In [26], the algebraico-tree-theoretic simplicity hierarchical structure of J. H. Conway's ordered field of surreal numbers was brought to the fore and employed to provide necessary and sufficient conditions for an ordered field (ordered -vector space) to be isomorphic to an initial subfield (-subspace) of , i.e. a subfield (-subspace) of that is an initial subtree of . In this sequel to [15], piggybacking on the just-said results, analogous results are established for ordered exponential fields, making use of a slight generalization of Schmeling's conception of a transseries field. It is further shown that a wide range of ordered exponential fields are isomorphic to initial exponential subfields of . These include all models of , where is the reals expanded by a convergent Weierstrass system . Of these, those we call trigonometric-exponential fields are given particular attention. It is shown that the exponential functions on the initial trigonometric-exponential subfields of , which includes itself, extend to canonical exponential functions on their surcomplex counterparts. The image of the canonical map of the ordered exponential field of logarithmic-exponential transseries into is shown to be initial, as are the ordered exponential fields and .
Keywords
Cite
@article{arxiv.2002.07739,
title = {Surreal ordered exponential fields},
author = {Philip Ehrlich and Elliot Kaplan},
journal= {arXiv preprint arXiv:2002.07739},
year = {2021}
}
Comments
37 pages. This version contains new material on the relationship with transseries fields, including a restatement of the main theorem (Theorem 9.1). Accepted to the Journal of Symbolic Logic