English

Invariants Related to the Tree Property

Logic 2019-08-13 v4

Abstract

We consider global analogues of model-theoretic tree properties. The main objects of study are the invariants related to Shelah's tree property κcdt(T)\kappa_{\text{cdt}}(T), κsct(T)\kappa_{\text{sct}}(T), and κinp(T)\kappa_{\text{inp}}(T) and the relations that obtain between them. From strong colorings, we construct theories TT with κcdt(T)>κsct(T)+κinp(T)\kappa_{\text{cdt}}(T) > \kappa_{\text{sct}}(T) + \kappa_{\text{inp}}(T). We show that these invariants have distinct structural consequences, by investigating the decay of saturation in ultrapowers of models of TT, where TT is some theory with κcdt(T)\kappa_{\text{cdt}}(T), κsct(T)\kappa_{\text{sct}}(T), or κinp(T)\kappa_{\text{inp}}(T) large and bounded. This answers some questions of Shelah.

Keywords

Cite

@article{arxiv.1511.06453,
  title  = {Invariants Related to the Tree Property},
  author = {Nicholas Ramsey},
  journal= {arXiv preprint arXiv:1511.06453},
  year   = {2019}
}