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
The universal measure of nonstochastic objects
Vladimir Vovk
Hyperarithmetic directions can all be exceptional for Marstrand's projection theorem
Noam Greenberg, Daniel Turetsky
Open Problems in Mathematical Logic
George Barmpalias, Su Gao, Jialiang He et al.
An easy proof that there may be no P-points
David Chodounský, Osvaldo Guzmán, Jonathan Verner
Comments on Choiceless Chain Conditions
Constance Bromham, Asaf Karagila
Localic Esakia Duality via Conic Frames
Nesta van der Schaaf