1997/12/15 by Aleksander Błaszczyk, Saharon Shelah, Błaszczyk, Aleksander +1
Computer Science · Mathematics · #Advanced Algebra and Logic #Computability, Logic, AI Algorithms #FOS: Mathematics #General Topology (math.GN) #Logic (math.LO) #Rings, Modules, and Algebras
paper · pdf · doi:10.48550/arxiv.math/9712285
openalex publication_date 1997/12/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
It is shown that there exists a complete, atomless, sigma-centered Boolean algebra, which does not contain any regular countable subalgebra if and only if there exist a nowhere dense ultrafilter. Therefore the existence of such algebras is undecidable in ZFC.