Back to results

Texas Digital Library

Forcing ℵ1-free groups to be free.

Abstract

dc:description.abstract

ℵ1-free groups, abelian groups whose countable subgroups are free, are objects of both algebraic and set-theoretic interest. Illustrating this, we note that ℵ1-free groups, and in particular the question of when ℵ1-free groups are free, were central to the resolution of the Whitehead problem as undecidable. In elucidating the relationship between ℵ1-freeness and freeness, we prove the following result: an abelian group G is ℵ1-free in a countable transitive model of ZFC (and thus by absoluteness, in every transitive model of ZFC) if and only if it is free in some generic model extension. We would like to answer the more specific question of when an ℵ1-free group can be forced to be free while preserving the cardinality of the group. For groups of size ℵ1, we establish a necessary and sufficient condition for when such forcings are possible. We also identify both existing and novel forcings which force such ℵ1-free groups of size ℵ1 to become free with cardinal preservation. These forcings lay the groundwork for a larger project which uses forcing to explore various algebraic properties of ℵ1-free groups and develops new set-theoretical tools for working with them.

Author and committee

dc:creator, dc:contributor.*
Author dc:creator
  • Pasi, Alexandra V., 1993-
Contributors dc:contributor
  • Herden, Daniel.

Subjects

dc:subject × 2

Rights

dc:rights
Statement dc:rights
  • Worldwide access
  • Baylor University theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. Contact libraryquestions@baylor.edu for inquiries about permission.
Language dc:language
en

Identifiers

dc:identifier.*
Handle dc:identifier.uri
https://hdl.handle.net/2104/11485
OAI identifier oai:identifier
oai:tdl-ir.tdl.org:2104/11485

Chain of custody

source
Harvested from
Texas Digital Library
Base URL
tdl-ir.tdl.org/server/oai/request
Last updated
2026-07-27
Source record
OAI-PMH GetRecord
citation

Pasi, Alexandra V., 1993-. Forcing ℵ1-free groups to be free.. 2021. https://hdl.handle.net/2104/11485