Reducibility of equivalence relations arising from nonstationary ideals under large cardinal assumptions

David Asperó, Tapani Hyttinen, Vadim Kulikov, Miguel Moreno

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Working under large cardinal assumptions, we study the Borel-reducibility between equivalence relations modulo restrictions of the non-stationary ideal on some fixed cardinal \kappa. We show the consistency of E^{\lambda^{++},\lambda^{++}}_{\lambda\text{-club}}, the relation of equivalence modulo the non-stationary ideal restricted to S^{\lambda^{++}}_\lambda in the space (\lambda^{++})^{\lambda^{++}}, being continuously reducible to E^{2,\lambda^{++}}_{\lambda^+\text{-club}}, the relation of equivalence modulo the non-stationary ideal restricted to S^{\lambda^{++}}_{\lambda^+} in the space 2^{\lambda^{++}}. Then we show that for \kappa ineffable E^{2, \kappa}_{\text{reg}}, the relation of equivalence modulo the non-stationary ideal restricted to regular cardinals in the space 2^{\kappa}, is \Sigma^1_1-complete. We finish by showing, for \Pi_2^1-indescribable \kappa, that the isomorphism relation between dense linear orders of cardinality \kappa is \Sigma^1_1-complete.
Original languageEnglish
JournalNotre Dame Journal of Formal Logic
Volume60
Issue number4
Pages (from-to)665-682
Number of pages18
ISSN0029-4527
DOIs
Publication statusPublished - Nov 2019
MoE publication typeA1 Journal article-refereed

Fields of Science

  • BOREL REDUCIBILITY
  • equivalence relations
  • generalized Baire spaces
  • large cardinals
  • 111 Mathematics

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