A note on -ultrafilters and -points
The main result is that for λ strong limit singular failing the continuum hypothesis (i.e. ), a polarized partition theorem holds.
Soit un ensemble fini. Nous nous proposons ici d’établir des indices de distance entre les divers ensembles de parties de . Nous généraliserons pour cela, à , la notion de fonction caractéristique bien connue dans .
Using ♢ , we construct a rigid atomless Boolean algebra that has no uncountable antichain and that admits the elimination of the Malitz quantifier .
We prove in ZFC that there is a set and a surjective function H: A → ⟨0,1⟩ such that for every null additive set X ⊆ ⟨0,1), is null additive in . This settles in the affirmative a question of T. Bartoszyński.
We prove some properties of uniformly completely Ramsey null sets (for example, every hereditarily Menger set is uniformly completely Ramsey null).