English

A pathological o-minimal quotient

Logic 2019-11-26 v2

Abstract

We give an example of a definable quotient in an o-minimal structure which cannot be eliminated over any set of parameters, giving a negative answer to a question of Eleftheriou, Peterzil, and Ramakrishnan. Equivalently, there is an o-minimal structure M whose elementary diagram does not eliminate imaginaries. We also give a positive answer to a related question, showing that any imaginary in an o-minimal structure is interdefinable over an independent set of parameters with a tuple of real elements. This can be interpreted as saying that interpretable sets look "locally" like definable sets, in a sense which can be made precise.

Keywords

Cite

@article{arxiv.1404.3175,
  title  = {A pathological o-minimal quotient},
  author = {Will Johnson},
  journal= {arXiv preprint arXiv:1404.3175},
  year   = {2019}
}

Comments

Withdrawn; incorporated into arXiv:1911.10077

R2 v1 2026-06-22T03:49:00.033Z