English

Weakly 2-randoms and 1-generics in Scott sets

Logic 2017-11-02 v1

Abstract

Let SS be a Scott set, or even an ω\omega-model of WWKL\mathsf{WWKL}. Then for each ASA\in S, either there is XSX \in S that is weakly 2-random relative to AA, or there is XSX\in S that is 1-generic relative to AA. It follows that if A1,,AnSA_1,\dots, A_n \in S are non-computable, there is XSX \in S such that each AiA_i is Turing incomparable with XX, answering a question of Ku\v{c}era and Slaman. More generally, any \forall\exists sentence in the language of partial orders that holds in D\mathcal D also holds in DS\mathcal D_S, where DS\mathcal D_S is the partial order of Turing degrees of elements of SS.

Keywords

Cite

@article{arxiv.1711.00153,
  title  = {Weakly 2-randoms and 1-generics in Scott sets},
  author = {Linda Brown Westrick},
  journal= {arXiv preprint arXiv:1711.00153},
  year   = {2017}
}

Comments

3 pages

R2 v1 2026-06-22T22:32:22.925Z