We have the following indirect implication of form equivalence classes:
Implication | Reference |
---|---|
3 \(\Rightarrow\) 9 |
Cardinal addition and the axiom of choice, Howard, P. 1974, Bull. Amer. Math. Soc. |
9 \(\Rightarrow\) 128 |
Realisierung und Auswahlaxiom, Brunner, N. 1984f, Arch. Math. (Brno) |
Here are the links and statements of the form equivalence classes referenced above:
Howard-Rubin Number | Statement |
---|---|
3: | \(2m = m\): For all infinite cardinals \(m\), \(2m = m\). |
9: | Finite \(\Leftrightarrow\) Dedekind finite: \(W_{\aleph_{0}}\) Jech [1973b]: \(E(I,IV)\) Howard/Yorke [1989]): Every Dedekind finite set is finite. |
128: | Aczel's Realization Principle: On every infinite set there is a Hausdorff topology with an infinite set of non-isolated points. |
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