English

Pure $\Sigma_2$-Elementarity beyond the Core

Logic 2021-06-10 v5

Abstract

We display the entire structure R2{\cal R}_2 coding Σ1\Sigma_1- and Σ2\Sigma_2-elementarity on the ordinals. This will enable the analysis of pure Σ3\Sigma_3-elementary substructures.

Cite

@article{arxiv.1710.01870,
  title  = {Pure $\Sigma_2$-Elementarity beyond the Core},
  author = {Gunnar Wilken},
  journal= {arXiv preprint arXiv:1710.01870},
  year   = {2021}
}

Comments

Extensive rewrite of the previous version of the paper according to reviewers' recommendations. The paper was corrected, improved, and extended considerably to become readable as stand-alone text. Numerous instructive examples were added. The introduction was extended and a figure added. The preprint is in final form and the corresponding article in press

R2 v1 2026-06-22T22:04:15.324Z