22 research outputs found

    The Galvin property under the Ultrapower Axiom

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    We continue the study of the Galvin property. In particular, we deepen the connection between certain diamond-like principles and non-Galvin ultrafilters. We also show that any Dodd sound ultrafilter that is not a pp-point is non-Galvin. We use these ideas to formulate an essentially optimal large cardinal hypothesis that ensures the existence of a non-Galvin ultrafilter, improving on results of Benhamou and Dobrinen. Finally, we use a strengthening of the Ultrapower Axiom to prove that in all the known canonical inner models, a Îș\kappa-complete ultrafilter on Îș\kappa has the Galvin property if and only if it is an iterated sum of pp-points

    Transferring Compactness

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    We demonstrate that the technology of Radin forcing can be used to transfer compactness properties at a weakly inaccessible but not strong limit cardinal to a strongly inaccessible cardinal. As an application, relative to the existence of large cardinals, we construct a model of set theory in which there is a cardinal Îș\kappa that is nn-dd-stationary for all n∈ωn\in \omega but not weakly compact. This is in sharp contrast to the situation in the constructible universe LL, where Îș\kappa being (n+1)(n+1)-dd-stationary is equivalent to Îș\kappa being Πn1\mathbf{\Pi}^1_n-indescribable. We also show that it is consistent that there is a cardinal Îș≀2ω\kappa\leq 2^\omega such that PÎș(λ)P_\kappa(\lambda) is nn-stationary for all λ≄Îș\lambda\geq \kappa and n∈ωn\in \omega, answering a question of Sakai.Comment: Corrected some typo

    A Small Ultrafilter Number at Every Singular Cardinal

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    We obtain a small ultrafilter number at ℔ω1\aleph_{\omega_1}. Moreover, we develop a version of the overlapping strong extender forcing with collapses which can keep the top cardinal Îș\kappa inaccessible. We apply this forcing to construct a model where Îș\kappa is the least inaccessible and VÎșV_\kappa is a model of GCH at regulars, failures of SCH at singulars, and the ultrafilter numbers at all singulars are small

    Galvin's property at large cardinals and the axiom of determinancy

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    In the first part of this paper, we explore the possibility for a very large cardinal Îș\kappa to carry a Îș\kappa-complete ultrafilter without Galvin's property. In this context, we prove the consistency of every ground model Îș\kappa-complete ultrafilter extends to a non-Galvin one. Oppositely, it is also consistent that every ground model Îș\kappa-complete ultrafilter extends to a PP-point ultrafilter, hence to another one satisfying Galvin's property. We also study Galvin's property at large cardinals in the choiceless context, especially under \textsf{AD}. Finally, we apply this property to a classical pro\-blem in partition calculus by proving the relation λ→(λ,ω+1)2\lambda\rightarrow(\lambda,\omega+1)^2 under ``\textsf{AD}+V=L(R)V=L(\mathbb{R})'' for unboundedly many λ>cf(λ)>ω\lambda>{\rm cf}(\lambda)>\omega below Θ\Theta

    Kurepa trees and the failure of the Galvin property

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    We force the existence of a non-trivial Îș\kappa-complete ultrafilter over Îș\kappa which fails to satisfy the Galvin property. This answers a question asked by the first author and Moti Gitik

    Silver-Free Palladium-Catalyzed C(sp3)H Arylation of Saturated Bicyclic Amine Scaffolds

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    Herein, we report a silver-free Pd(II)-catalyzed C(sp3)-H arylation of saturated bicyclic and tricyclic amine scaffolds. The reaction provides good yields using a range of aryl iodides and aryl bromides including functionalized examples bearing aldehydes, ketones, esters, free phenols, and heterocycles. The methodology has been applied to medicinally relevant scaffolds. Two of the intermediate palladium complexes in the catalytic cycle have been prepared and characterized, and a mechanism is proposed. Removal of the directing group proceeded with good yield under relatively mild conditions
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