324 citations · 1.7k across the 753 of their papers we have counts for
40 papers · 1 filter
The condition in the Trichotomy Theorem is optimal
Menachem Kojman, Saharon Shelah
We show that the assumption lambda > kappa^+ in the Trichotomy Theorem cannot be relaxed to lambda > kappa .
The covering numbers of Mycielski ideals are all equal
Saharon Shelah, Juris Steprāns
The Mycielski ideal M_k is defined to consist of all sets A subseteq k^omega such that {f restriction X: f in A} not= k^X for all X in [omega]^{aleph_0}. It will be shown that the…
Complete sigma-centered Boolean algebra not adding Cohen reals
Aleksander Błaszczyk, Saharon Shelah
It is shown that there exists a complete, atomless, sigma-centered Boolean algebra, which does not contain any regular countable subalgebra if and only if there exist a nowhere den…
More on the lifting problem with the full ideal
Saharon Shelah
We prove in ZFC that for mu >= aleph_2 there is a sigma --ideal I on mu and a Boolean sigma --subalgebra B of the family of subsets of mu which includes I such that the natural hom…
Non-elementary proper forcing notions
Saharon Shelah
We present reasons for developing a theory of forcing notions which satisfy the properness demand for countable models which are not necessarily elementary submodels of some (H(chi…
Was Sierpinski right? IV
Saharon Shelah
We prove for any mu = mu^{< mu}< theta < lambda, lambda large enough (just strongly inaccessible Mahlo) the consistency of 2^mu = lambda-> [theta]^2_3 and even 2^mu = lambda-> [the…