Densities of ultraproducts of Boolean algebras
Sabine Koppelberg, Saharon Shelah
Abstract
We answer three problems by J. D. Monk on cardinal invariants of Boolean algebras. Two of these are whether taking the algebraic density pi(A), resp. the topological density d(A), of a Boolean algebra A commutes with formation of ultraproducts; the third one compares the number of endomorphisms and of ideals of a Boolean algebra.
Create a lesson
Related papers
Friedman--Stanley cofinality without Borel completeness
Ruijun Wang
On Farah ideals and beyond
Adam Kwela
The 1-2-3 Conjecture for Borel Combinatorics
Junhao Chen, Wei Dai
No Borel upper bound for the Fσ equivalence relations
Ruijun Wang
Omitting Types for Infinitary Real-Valued Logic: A Topological Perspective
Olivia Aubone, Eduardo Dueñez, José Iovino
1-Genericity Is Not Weihrauch Reducible to the Finite Intersection Principle
Patrizio Cintioli