منابع مشابه
Boolean Ultrapowers, the Bukovský-dehornoy Phenomenon, and Iterated Ultrapowers
We show that while the length ω iterated ultrapower by a normal ultrafilter is a Boolean ultrapower by the Boolean algebra of Př́ıkrý forcing, it is consistent that no iteration of length greater than ω (of the same ultrafilter and its images) is a Boolean ultrapower. For longer iterations, where different ultrafilters are used, this is possible, though, and we give Magidor forcing and a general...
متن کاملGame values and equilibria for undetermined sentences of Dependence Logic
Logics of imperfect information, such as IF-Logic or Dependence Logic, admit a game-theoretic semantics: every formula φ corresponds to a gameH(φ) between a Verifier and a Falsifier, and the formula is true [false] if and only if the Verifier [Falsifier] has a winning strategy. Since the rule of the excluded middle does not hold in these logics, it is possible for a game H(φ) to be undetermined...
متن کاملFresh subsets of ultrapowers
In [8], Shelah and Stanley constructed a κ-Aronszjan tree with an ascent path using κ. We show that κ,2 does not imply the existence of Aronszajn trees with ascent paths. The proof goes through an intermediate combinatorial principle, which we investigate further.
متن کاملOn the Cofinality of Ultrapowers
We prove some restrictions on the possible cofinalities of ultrapowers of the natural numbers with respect to ultrafilters on the natural numbers. The restrictions involve two cardinal characteristics of the continuum, the splitting number s and the groupwise density number g.
متن کاملOn Partially Wellfounded Generic Ultrapowers
We construct a model without precipitous ideals but so that for each τ < א3 there is a normal ideal over א1 with generic ultrapower wellfounded up to the image of τ .
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Annals of Pure and Applied Logic
سال: 1993
ISSN: 0168-0072
DOI: 10.1016/0168-0072(93)90078-r