Coding with ladders a well ordering of the reals

Uri Abraham, Saharon Shelah

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Any model of ZFC + GCH has a generic extension (made with a poset of size N2) in which the following hold: MA + 2N0 = N2+there exists a Δ1 2-well ordering of the reals. The proof consists in iterating posets designed to change at will the guessing properties of ladder systems on ω1. Therefore, the study of such ladders is a main concern of this article.

Original languageEnglish
Pages (from-to)579-597
Number of pages19
JournalJournal of Symbolic Logic
Issue number2
StatePublished - 1 Jan 2002

ASJC Scopus subject areas

  • Philosophy
  • Logic


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