English

Normal hyperimaginaries

Logic 2013-12-06 v3

Abstract

We introduce the notion of normal hyperimaginary and we develop its basic theory. We present a new proof of Lascar-Pillay's theorem on bounded hyperimaginaries based on properties of normal hyperimaginaries. However, the use of Peter-Weyl's theorem on the structure of compact Hausdorff groups is not completely eliminated from the proof. In the second part, we show that all closed sets in Kim-Pillay spaces are equivalent to hyperimaginaries and we use this to introduce an approximation of φ\varphi-types for bounded hyperimaginaries.

Cite

@article{arxiv.1112.2049,
  title  = {Normal hyperimaginaries},
  author = {Enrique Casanovas and Joris Potier},
  journal= {arXiv preprint arXiv:1112.2049},
  year   = {2013}
}
R2 v1 2026-06-21T19:48:45.704Z