A note on dual Dedekind finiteness
Abstract A set $A$ is dually Dedekind finite if every surjection from $A$ onto $A$ is injective; otherwise, $A$ is dually Dedekind infinite. It is proved consistent with $\mathsf{ZF}$ (i.e. the Zermelo–Fraenkel set theory without the axiom of choice) that there exists a family $\langle A_{n}\rangle _{n\in \omega }$ of sets such that, for all $n\in \omega $, $A_{n}^{n}$ is dually Dedekind finite whereas $A_{n}^{n+1}$ is dually Dedekind infinite. This resolves a question that was left open in (Classes of Dedekind finite cardinals. Fund. Math. 1974;84:187–208).
Authors
- Guozhen Shen (ORCID: https://orcid.org/0000-0003-0100-2318)
- Ruihuan Mao
Institutions
- Nankai University (CN)
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) (CN)
Publication Details
- Journal
- Logic Journal of IGPL
- Published
- 2025-08-15
- DOI
- https://doi.org/10.1093/jigpal/jzaf069
- Citations
- 1
- Primary Topic
- Advanced Topology and Set Theory
- Type
- article
- Field-Weighted Citation Impact
- 4.09