324 citations · 1.7k across the 753 of their papers we have counts for
35 papers · 2 filters
Potential isomorphism and semi-proper trees
Alex Hellsten, Tapani Hyttinen, Saharon Shelah
We study a notion of potential isomorphism, where two structures are said to be potentially isomorphic if they are isomorphic in some generic extension that preserves stationary se…
Specializing Aronszajn trees by countable approximations
Heike Mildenberger, Saharon Shelah
We show that there are proper forcings based upon countable trees of creatures that specialize a given Aronszajn tree.
Forcing axiom failure for any lambda>aleph_1
Saharon Shelah
David Aspero asks on the possibility of having Forcing axiom FA_{aleph_2}(K), where K is the class of forcing notions preserving stationarity of subsets of aleph_1 and of aleph_2.…
Characterizing automorphism groups of ordered abelian groups
Rüdiger Göbel, Saharon Shelah
We characterize the groups isomorphic to full automorphism groups of ordered abelian groups. The result will follow from classical theorems on ordered groups adding an argument fro…
Kulikov's problem on universal torsion-free abelian groups
Saharon Shelah, Lutz Strüngmann
Let T be an abelian group and lambda an uncountable regular cardinal. We consider the question of whether there is a lambda-universal group G^* among all torsion-free abelian group…
On universal and epi-universal locally nilpotent groups
Rüdiger Göbel, Saharon Shelah, Simone Wallutis
In this paper we mainly consider the class LN of all locally nilpotent groups. We first show that there is no universal group in LN_lambda if lambda is a cardinal such that lambda…