This non-implication,
Form 122 \( \not \Rightarrow \)
Form 29,
whose code is 4, is constructed around a proven non-implication as follows:
| Hypothesis | Statement |
|---|---|
| Form 165 | <p> \(C(WO,WO)\): Every well ordered family of non-empty, well orderable sets has a choice function. </p> |
| Conclusion | Statement |
|---|---|
| Form 31 | <p>\(UT(\aleph_{0},\aleph_{0},\aleph_{0})\): <strong>The countable union theorem:</strong> The union of a denumerable set of denumerable sets is denumerable. </p> |
The conclusion Form 122 \( \not \Rightarrow \) Form 29 then follows.
Finally, the
List of models where hypothesis is true and the conclusion is false:
| Name | Statement |
|---|---|
| \(\cal M12(\aleph)\) Truss' Model I | This is a variation of Solovay's model, <a href="/models/Solovay-1">\(\cal M5(\aleph)\)</a> in which \(\aleph\) is singular |
| \(\cal M20\) Felgner's Model I | Let \(\cal M\) be a model of \(ZF + V = L\). Felgner defines forcing conditions that force \(\aleph_{\omega}\) in \(\cal M\) to be \(\aleph_1\) |