7 citations · 16 across the 8 of their papers we have counts for
8 papers · 1 filter
Nonproper Products
Andrzej Roslanowski, Saharon Shelah, Otmar Spinas
We show that there exist two proper creature forcings having a simple (Borel) definition, whose product is not proper. We also give a new condition ensuring properness of some forc…
On incomparability and related cardinal functions on ultraproducts of Boolean algebras
Saharon Shelah, Otmar Spinas
Let C denote any of the following cardinal characteristics of Boolean algebras: incomparability, spread, character, pi-character, hereditary Lindelof number, hereditary density. It…
On tightness and depth in superatomic Boolean algebras
Saharon Shelah, Otmar Spinas
We introduce a large cardinal property which is consistent with L and show that for every superatomic Boolean algebra B and every cardinal lambda with the large cardinal property,…
The distributivity numbers of finite products of P(omega) /fin
Saharon Shelah, Otmar Spinas
Generalizing [ShSi:494], for every n< omega we construct a ZFC-model where the distributivity number of r.o. (P(omega)/fin)^{n+1}, h(n+1), is smaller than the one of r.o.(P(omega)/…
The distributivity numbers of of P(om) /fin and its square
Saharon Shelah, Otmar Spinas
We show that in a model obtained by forcing with a countable support iteration of length omega_2 of Mathias forcing h(2), the distributivity number of r.o.(P(omega)/fin)^2, is omeg…
On Gross spaces
Saharon Shelah, Otmar Spinas
A Gross space is a vector space E of infinite dimension over some field F, which is endowed with a symmetric bilinear form Phi:E^2 -> F and has the property that every infinite dim…