22 research outputs found
The Galvin property under the Ultrapower Axiom
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 -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 -complete ultrafilter on has the Galvin property if and only
if it is an iterated sum of -points
Transferring Compactness
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 that is
--stationary for all but not weakly compact. This is in
sharp contrast to the situation in the constructible universe , where
being --stationary is equivalent to being
-indescribable. We also show that it is consistent that there
is a cardinal such that is
-stationary for all and , answering a
question of Sakai.Comment: Corrected some typo
A Small Ultrafilter Number at Every Singular Cardinal
We obtain a small ultrafilter number at . Moreover, we
develop a version of the overlapping strong extender forcing with collapses
which can keep the top cardinal inaccessible. We apply this forcing to
construct a model where is the least inaccessible and 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
In the first part of this paper, we explore the possibility for a very large
cardinal to carry a -complete ultrafilter without Galvin's
property. In this context, we prove the consistency of every ground model
-complete ultrafilter extends to a non-Galvin one. Oppositely, it is
also consistent that every ground model -complete ultrafilter extends
to a -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
under
``\textsf{AD}+'' for unboundedly many below
Kurepa trees and the failure of the Galvin property
We force the existence of a non-trivial -complete ultrafilter over
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
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