A solution to Roitman's problem
Abstract
We answer Question~3.2 from Shelah \cite{Sh:666}: Given a maximal almost disjoint (mad) family of size , we construct a forcing that has Axiom A, is -bounding, preserves selective ultrafilters, has the -properness isomorphism condition (p.i.c.), and destroys the mad family . We develop a new construction technique for partial orders, combining ladder systems for with trees of normed creatures. Countable support iteration of the new kind of iterands solves Roitman's problem in the case of and also simultaneously the open question about the relative consistency of : It is consistent relative to ZFC that there is a dominating set of size and a selective ultrafilter with character and the minimal size of a mad family is , like the continuum.
Cite
@article{arxiv.1404.7343,
title = {A solution to Roitman's problem},
author = {Heike Mildenberger},
journal= {arXiv preprint arXiv:1404.7343},
year = {2015}
}
Comments
20 pages Lemma 3.2 is flawed The author thanks Jindrich Zapletal