English

Shelah's eventual categoricity conjecture in tame AECs with primes

Logic 2018-05-07 v6

Abstract

A new case of Shelah's eventual categoricity conjecture is established: Theorem\mathbf{Theorem} Let KK be an AEC with amalgamation. Write H2:=(2(2LS(K))+)+H_2 := \beth_{\left(2^{\beth_{\left(2^{\text{LS} (K)}\right)^+}}\right)^+}. Assume that KK is H2H_2-tame and KH2K_{\ge H_2} has primes over sets of the form M{a}M \cup \{a\}. If KK is categorical in some λ>H2\lambda > H_2, then KK is categorical in all λH2\lambda' \ge H_2. The result had previously been established when the stronger locality assumptions of full tameness and shortness are also required. An application of the method of proof of the theorem is that Shelah's categoricity conjecture holds in the context of homogeneous model theory (this was known, but our proof gives new cases): Theorem\mathbf{Theorem} Let DD be a homogeneous diagram in a first-order theory TT. If DD is categorical in a λ>T\lambda > |T|, then DD is categorical in all λmin(λ,(2T)+)\lambda' \ge \min (\lambda, \beth_{(2^{|T|})^+}).

Keywords

Cite

@article{arxiv.1509.04102,
  title  = {Shelah's eventual categoricity conjecture in tame AECs with primes},
  author = {Sebastien Vasey},
  journal= {arXiv preprint arXiv:1509.04102},
  year   = {2018}
}

Comments

16 pages. Generalizes arXiv:1506.07024