<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"> <mml:mrow> <mml:mi mathvariant="sans-serif">MA</mml:mi> </mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mi mathvariant="script">I</mml:mi> </mml:math> ) and a failure of
We present a method which forces the failure of Π 3 1 and Σ 3 1 -separation, while MA ( I ) holds, for I the family of indestructible ccc forcings. This shows that, in contrast to the assumption BPFA and ℵ 1 = ℵ 1 L which implies Π 3 1 -separation, that weaker forcing axioms do not decide separation on the third projective level.
Authors
- Stefan Hoffelner (ORCID: https://orcid.org/0000-0003-0434-6554)
Institutions
- TU Wien (AT)
Publication Details
- Journal
- Annals of Pure and Applied Logic
- Published
- 2025-10-20
- DOI
- https://doi.org/10.1016/j.apal.2025.103667
- Primary Topic
- Advanced Topology and Set Theory
- Type
- article
- Field-Weighted Citation Impact
- 0.00