This non-implication,
Form 87-alpha \( \not \Rightarrow \)
Form 259,
whose code is 4, is constructed around a proven non-implication as follows:
Hypothesis | Statement |
---|---|
Form 87-alpha | <p> \(DC(\aleph_{\alpha})\): Given a relation \(R\) such that for every subset \(Y\) of a set \(X\) with \(|Y|<\aleph_{\alpha}\), there is an \(x\in X\) with \(Y\mathrel R x\) then there is a function \(f:\aleph_{\alpha}\to X\) such that (\(\forall\beta < \aleph_{\alpha}\)) \(\{f(\gamma): \gamma < \beta\}\mathrel R f(\beta)\). </p> |
Conclusion | Statement |
---|---|
Form 51 | <p> <strong>Cofinality Principle:</strong> Every linear ordering has a cofinal sub well ordering. <a href="/articles/Sierpi\'nski-1918">Sierpi\'nski [1918]</a>, p 117. </p> |
The conclusion Form 87-alpha \( \not \Rightarrow \) Form 259 then follows.
Finally, the
List of models where hypothesis is true and the conclusion is false:
Name | Statement |
---|---|
\(\cal M40(\kappa)\) Pincus' Model IV | The ground model \(\cal M\), is a model of \(ZF +\) the class form of \(AC\) |