324 citations · 1.7k across the 753 of their papers we have counts for
11 papers · 1 filter
Large strongly anti-Urysohn spaces exist
István Juhász, Saharon Shelah, LAjos Soukup +1
As defined in [1], a Hausdorff space is strongly anti-Urysohn (in short: SAU) if it has at least two non-isolated points and any two infinite} closed subsets of it intersect. Our m…
Countably compact groups without non-trivial convergent sequences
Michael Hrušák, Jan van Mill, Ulises Ariet Ramos-García +1
We construct, in , a countably compact subgroup of without non-trivial convergent sequences, answering an old problem of van Douwen. As a consequen…
Pseudo P-points and splitting number
Alan Dow, Saharon Shelah
We construct a model in which the splitting number is large and every ultrafilter has a small subset with no pseudo-intersection.
Asymmetric tie-points and almost clopen subsets of N*
Alan Dow, Saharon Shelah
A tie-point of a compact space is analogous to a cut-point: the complement of the point falls apart into two relatively clopen non-compact subsets. Set-theoretically a tie-point of…
The linear refinement number and selection theory
Michał Machura, Saharon Shelah, Boaz Tsaban
The \emph{linear refinement number} is the minimal cardinality of a centered family in such that no linearly ordered set in refines th…
Strong colorings yield kappa-bounded spaces with discretely untouchable points
Istvan Juhasz, Saharon Shelah
It is well-known that every non-isolated point in a compact Hausdorff space is the accumulation point of a discrete subset. Answering a question raised by Z. Szentmiklossy and the…