Problem #5
Does the Partition Principle imply the Axiom of Choice?
The Partition Principle () states that for any sets and , if there is a surjection from to then there is an injection from to . This question asks whether the Partition Principle implies the Axiom of Choice over .
Known Partial Results
- Pincus proved that implies that every well-ordered family of nonempty sets has a choice function.
- By a result of Jensen, the above theorem of Pincus shows that also implies , the Axiom of Dependent Choice.
Notes
This question was first posed in the early 1900s and is one of the oldest open problems in set theory.
Reference for the problem statement
[BM90]Bernhard Banaschewski and Gregory H. Moore, The dual Cantor-Bernstein theorem and the partition principle, Notre Dame Journal of Formal Logic, 1990 [doi]
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