Session 32. Set Theory

Full splitting Miller trees and ioe reals

Giorgio Laguzzi, Universität Hamburg, Germany
The talk is based on the joint work with Yurii Khomskii
We investigate two tree forcings for adding infinitely often equal reals: the full splitting Miller forcing \(\mathbb{FM}\), introduced by Rosłanowski in [1], and the infinitely often equal trees forcing \(\mathbb{IE}\), implicitly introduced by Spinas in [2]. We prove results about Marczewski-type regularity properties associated with these forcings as well as dichotomy properties on \(\mathbf{\Delta}^1_2\) and \(\mathbf{\Sigma}^1_2\) levels, with a particular emphasis on a parallel with the Baire property. Furthermore, we prove that our dichotomies hold for all projective sets in Solovay's model, and that the use of an inaccessible is necessary for both.
References
  1. A. Rosłanowski, On game ideals , Colloq. Math., 59(2):159-168, 1990.
  2. O. Spinas, Perfect set theorems , Fund. Math., 201(2):179-195, 2008.
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