English

A symmetric $\beta$-model

Logic 2018-03-07 v1

Abstract

We prove that there exists a countable β\beta-model in which, for all reals XX and YY, XX is definable from YY if and only XX is hyperarithmetical in YY. We also obtain some related results and pose some related questions.

Keywords

Cite

@article{arxiv.1803.02336,
  title  = {A symmetric $\beta$-model},
  author = {Stephen G. Simpson},
  journal= {arXiv preprint arXiv:1803.02336},
  year   = {2018}
}

Comments

8 pages. This paper was written in 2000 but was not published until 2018. The only change since 2000 is that the references have been updated

R2 v1 2026-06-23T00:44:14.027Z