English

The Karp complexity of unstable classes

Logic 2007-05-23 v1

Abstract

A class K of structures is controlled if, for all cardinals lambda, the relation of L_{infty,lambda}-equivalence partitions K into a set of equivalence classes (as opposed to a proper class). We prove that the class of doubly transitive linear orders is controlled, while any pseudo-elementary class with the omega-independence property is not controlled.

Keywords

Cite

@article{arxiv.math/0011167,
  title  = {The Karp complexity of unstable classes},
  author = {Michael C. Laskowski and Saharon Shelah},
  journal= {arXiv preprint arXiv:math/0011167},
  year   = {2007}
}