English

A model with fragments of projective determinacy and failures of $\mathsf{DC}$

Logic 2025-05-23 v1

Abstract

We describe a construction of a model of second order arithmetic in which (boldface) Πn1\bm{\Pi^1_n}-determinacy holds, but (lightface) Πn+21\Pi^1_{n+2}-DC\mathsf{DC} fails, thus showing that no projective level of determinacy implies full DCR\mathsf{DC}_{\mathbb{R}}. The construction builds upon the work of Gitman, Friedman, and Kanovei.

Keywords

Cite

@article{arxiv.2505.16628,
  title  = {A model with fragments of projective determinacy and failures of $\mathsf{DC}$},
  author = {Sandra Müller and Bartosz Wcisło},
  journal= {arXiv preprint arXiv:2505.16628},
  year   = {2025}
}

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17 pages