Article contents
On relatively analytic and Borel subsets
Published online by Cambridge University Press: 12 March 2014
Abstract
Define to be the smallest cardinality of a function f: X→Y with I, X, Y, ⊆ 2ω such that there is no Borel function g ⊇ f. In this paper we prove that it is relatively consistent with ZFC to have b <
where b is, as usual, smallest cardinality of an unbounded family in Ωω. This answers a question raised by Zapletal.
We also show that it is relatively consistent with ZFC that there exists X ⊆ 2ω such that the Borei order of X is bounded but there exists a relatively analytic subset of X which is not relatively coanalytic. This answers a question of Mauldin.
- Type
- Research Article
- Information
- Copyright
- Copyright © Association for Symbolic Logic 2005
References
REFERENCES
- 1
- Cited by