We have the following indirect implication of form equivalence classes:
| Implication | Reference |
|---|---|
| 8 \(\Rightarrow\) 9 | Was sind und was sollen die Zollen?, Dedekind, [1888] |
| 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 |
|---|---|
| 8: | \(C(\aleph_{0},\infty)\): |
| 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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