Provable Pi-1-2 Singletons
Sy D. Friedman
math.LOarXiv:math/9302201
Abstract
In this note I show that a pi-1-2 singleton R of L-degree strictly between 0 and 0# can be obtained so as to be the unique solution to a pi-1-2 formula which provably has at most one solution, in the theory ZFC+(*) where (*) has the approximate strength of an ineffable cardinal.
Create a lesson
Related papers
Friedman--Stanley cofinality without Borel completeness
Ruijun Wang
On Farah ideals and beyond
Adam Kwela
The 1-2-3 Conjecture for Borel Combinatorics
Junhao Chen, Wei Dai
No Borel upper bound for the Fσ equivalence relations
Ruijun Wang
Omitting Types for Infinitary Real-Valued Logic: A Topological Perspective
Olivia Aubone, Eduardo Dueñez, José Iovino
1-Genericity Is Not Weihrauch Reducible to the Finite Intersection Principle
Patrizio Cintioli