324 citations · 1.7k across the 753 of their papers we have counts for
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It is consistent with ZFC that B_1-groups are not B_2-groups
Saharon Shelah, Lutz Strüngmann
A torsion-free abelian group B of arbitrary rank is called a B_1-group if Bext^1(B,T)=0 for every torsion abelian group T, where Bext^1 denotes the group of equivalence classes of…
On ultraproducts of Boolean Algebras and irr
Saharon Shelah
We prove the consistency of irr(prod limits_{i<kappa}B_i/D)< prod limits_{i<kappa}irr(B_i)/D, where D is an ultrafilter on kappa and each B_i is a Boolean Algebra. This solves the…
Are a and d your cup of tea?
Saharon Shelah
We show that, consistently, every MAD family has cardinality strictly bigger than the dominating number, that is a > d, thus solving one of the oldest problems on cardinal invarian…
The non-commutative Specker phenomenon in the uncountable case
Katsuya Eda, Saharon Shelah
An infinitary version of the notion of free products has been introduced and investigated by G.Higman. Let G_i (for i in I) be groups and ast_{i in X} G_i the free product of G_i (…
Whitehead modules over large principal ideal domains
Paul C. Eklof, Saharon Shelah
We consider the Whitehead problem for principal ideal domains of large size. It is proved, in ZFC, that some p.i.d.'s of size >= aleph_{2} have non-free Whitehead modules even thou…
On Whitehead precovers
Paul C. Eklof, Saharon Shelah
It is proved undecidable in ZFC + GCH whether every Z-module has a^{perp} {Z}-precover.