The structure of pleasant ideals
Christopher Leary
Abstract
Normal ideals on regular uncountable cardinals are familiar objects. We investigate ideals that are pleasant--while a normal ideal is closed under arbitrary diagonal unions, a pleasant ideal is closed only under diagonal unions indexed by sets that are elements of the ideal. We show any selective ideal extending the nonstationary ideal must be normal.
Create a lesson
Related papers
Pseudofinite abelian groups and asymptotic classes of finite abelian groups
Carlos Cordoba-Caycedo, Dario Garcia
Spectral Theory and Descriptive Combinatorics for Non-Regular Borel pmp Graphs
Cecelia Higgins, Pieter Spaas, Sofia Torelli
The strength of the minimum principle in constructive reverse mathematics
Tatsuji Kawai
Independence of premise for intuitionistic Zermelo-Fraenkel set theory
Patrick Uftring
Condensed Whitehead Problem
Spencer Unger, Jerry Wei
Points and their multiples on curves in powers of simple abelian varieties
David J. Smith