On the Tukey types of Fubini products
We extend the class of ultrafilters $ U $ over countable sets for which $ U\cdot U\equiv_T U
$, extending several results from\cite {Dobrinen/Todorcevic11}. In particular, we prove that …
$, extending several results from\cite {Dobrinen/Todorcevic11}. In particular, we prove that …
Chains of P-points
Chains of P-points Page 1 http://dx.doi.org/. /S ©Canadian Mathematical Society Chains of P-points
Dilip Raghavan and Jonathan L. Verner Abstract. It is proved that the Continuum Hypothesis …
Dilip Raghavan and Jonathan L. Verner Abstract. It is proved that the Continuum Hypothesis …
Cofinal types of ultrafilters over measurable cardinals
We develop the theory of cofinal types of ultrafilters over measurable cardinals and establish
its connections to Galvin's property. We generalize fundamental results from the countable to …
its connections to Galvin's property. We generalize fundamental results from the countable to …
PCF theory and the Tukey spectrum
T Gilton - arxiv preprint arxiv:2211.13361, 2022 - arxiv.org
In this paper, we investigate the relationship between the Tukey order and PCF theory, as
applied to sets of regular cardinals. We show that it is consistent that for all sets $ A $ of …
applied to sets of regular cardinals. We show that it is consistent that for all sets $ A $ of …
Order structure of P-point ultrafilters and their relatives
We survey some recent results about the order structure of various kinds of ultrafilters. More
precisely, we study Rudin-Keisler and Tukey reducibility in classes of selective, stable …
precisely, we study Rudin-Keisler and Tukey reducibility in classes of selective, stable …
Initial Tukey structure below a stable ordered-union ultrafilter
T Özalp - arxiv preprint arxiv:2410.04326, 2024 - arxiv.org
Answering a question of Dobrinen and Todorcevic, we prove that below any stable ordered-
union ultrafilter $\mathcal {U} $, there are exactly four nonprincipal Tukey classes: $[\mathcal …
union ultrafilter $\mathcal {U} $, there are exactly four nonprincipal Tukey classes: $[\mathcal …
[PDF][PDF] Q-points in the Tukey order
D Raghavan - arxiv preprint arxiv:2410.20216, 2024 - arxiv.org
The purpose of this note is to address a question that has been considered in two recent
papers, namely the existence of Tukey maximal Q-points. This was asked in [2] and …
papers, namely the existence of Tukey maximal Q-points. This was asked in [2] and …
Cofinal types on ω2
B Kuzeljevic, S Todorcevic - Mathematical Logic Quarterly, 2023 - Wiley Online Library
In this paper we start the analysis of the class D ℵ 2 D_ℵ_2, the class of cofinal types of
directed sets of cofinality at most ℵ2. We compare elements of D ℵ 2 D_ℵ_2 using the …
directed sets of cofinality at most ℵ2. We compare elements of D ℵ 2 D_ℵ_2 using the …
Lower Bounds of Sets of P-points
Lower Bounds of Sets of P-points Page 1 Notre Dame Journal of Formal Logic Volume 64,
Number 3, 2023 Lower Bounds of Sets of P-points Borisa Kuzeljevic, Dilip Raghavan, and …
Number 3, 2023 Lower Bounds of Sets of P-points Borisa Kuzeljevic, Dilip Raghavan, and …
THE RUDIN–KEISLER ORDERING OF P-POINTS UNDER 𝔟= 𝔠
A Starosolski - The Journal of Symbolic Logic, 2021 - cambridge.org
ME Rudin (1971) proved, under CH, that for each P-point p there exists a P-point q strictly
RK-greater than p. This result was proved under by A. Blass (1973), who also showed that …
RK-greater than p. This result was proved under by A. Blass (1973), who also showed that …