English

Definably compact groups definable in real closed fields.II

Logic 2017-05-23 v1

Abstract

We continue the analysis of definably compact groups definable in a real closed field R\mathcal{R}. In [3], we proved that for every definably compact definably connected semialgebraic group GG over R\mathcal{R} there are a connected RR-algebraic group HH, a definable injective map ϕ\phi from a generic definable neighborhood of the identity of GG into the group H(R)H\left(R\right) of RR-points of HH such that ϕ\phi acts as a group homomorphism inside its domain. The above result and our study of locally definable covering homomorphisms for locally definable groups combine to prove that if such group GG is in addition abelian, then its o-minimal universal covering group G~\widetilde{G} is definably isomorphic, as a locally definable group, to a connected open locally definable subgroup of the o-minimal universal covering group H(R)0~\widetilde{H\left(R\right)^{0}} of the group H(R)0H\left(R\right)^{0} for some connected RR-algebraic group HH.

Keywords

Cite

@article{arxiv.1705.07370,
  title  = {Definably compact groups definable in real closed fields.II},
  author = {Eliana Barriga},
  journal= {arXiv preprint arXiv:1705.07370},
  year   = {2017}
}
R2 v1 2026-06-22T19:53:39.089Z