How high can Baumgartner’s $${\mathcal{I}}$$ I -ultrafilters lie in the P-hierarchy?
Crossref DOI link: https://doi.org/10.1007/s00153-015-0427-x
Published Online: 2015-04-02
Published Print: 2015-08
Update policy: https://doi.org/10.1007/springer_crossmark_policy
Machura, Michał
Starosolski, Andrzej
License valid from 2015-04-02