English

Perfect set dichotomy theorem in generalized Solovay model

Logic 2025-12-04 v1

Abstract

We prove that the perfect set dichotomy theorem holds in the Solovay model V((ωω)V[G])V ((\omega^\omega)^{V[G]}). Namely, for every equivalence relation EE on R\mathbb{R}, either R/E\mathbb{R}/E is well-orderable or there exists a perfect set consisting of EE-inequivalent reals. Furthermore we consider a generalization of the Solovay model for an uncountable regular cardinal μ\mu and show the perfect set dichotomy theorem for μμ\mu^\mu also holds in that model. We establish the three element basis theorem for uncountable linear orders in the Solovay model for a weakly compact cardinal, in a general form covering the uncountable case.

Keywords

Cite

@article{arxiv.2512.03386,
  title  = {Perfect set dichotomy theorem in generalized Solovay model},
  author = {Hiroshi Sakai and Toshimasa Tanno},
  journal= {arXiv preprint arXiv:2512.03386},
  year   = {2025}
}

Comments

24pages

R2 v1 2026-07-01T08:06:57.692Z