Maximal almost disjoint families, determinacy, and forcing
Logic
2022-10-07 v1
Abstract
We study the notion of -MAD families where is a Borel ideal on . We show that if is an arbitrary ideal, or is any finite or countably iterated Fubini product of ideals, then there are no analytic infinite -MAD families, and assuming Projective Determinacy there are no infinite projective -MAD families; and under the full Axiom of Determinacy + there are no infinite -mad families. These results apply in particular when is the ideal of finite sets , which corresponds to the classical notion of MAD families. The proofs combine ideas from invariant descriptive set theory and forcing.
Cite
@article{arxiv.1810.03016,
title = {Maximal almost disjoint families, determinacy, and forcing},
author = {Karen Bakke Haga and David Schrittesser and Asger Törnquist},
journal= {arXiv preprint arXiv:1810.03016},
year = {2022}
}
Comments
40 pages