English

Weakening the local character

Logic 2011-05-19 v1

Abstract

In [Sh E46], Shelah obtained a non-forking relation for an AEC, (K,\preceq), with LST-number at most \lambda, which is categorical in \lambda and \lambda^+ and has less than 2^{\lambda^+} models of cardinality \lambda^{++}, but at least one. This non-forking relation satisfies the main properties of the non-forking relation on stable first order theories, but only a weak version of the local character. Here, we improve this non-forking relation such that it satisfies the local character, too. Therefore it satisfies the main properties of the non-forking relation on superstable first order theories. We conclude that the function \lambda \to I(\lambda,K), which assigns to each cardinal \lambda, the number of models in K of cardinality \lambda, is not arbitrary.

Keywords

Cite

@article{arxiv.1105.3674,
  title  = {Weakening the local character},
  author = {Adi Jarden and Saharon Shelah},
  journal= {arXiv preprint arXiv:1105.3674},
  year   = {2011}
}

Comments

11 pages

R2 v1 2026-06-21T18:09:12.519Z