We have the following indirect implication of form equivalence classes:
| Implication | Reference |
|---|---|
| 302 \(\Rightarrow\) 392 | clear |
| 392 \(\Rightarrow\) 394 | clear |
| 394 \(\Rightarrow\) 337 | clear |
| 337 \(\Rightarrow\) 92 | clear |
| 92 \(\Rightarrow\) 170 |
Non-constructive properties of the real numbers, Howard, P. 2001, Math. Logic Quart. |
| 170 \(\Rightarrow\) 93 | Zermelo's Axiom of Choice, Moore, [1982] |
Here are the links and statements of the form equivalence classes referenced above:
| Howard-Rubin Number | Statement |
|---|---|
| 302: | Any continuous surjection between compact Hausdorff spaces has an irreducible restriction to a closed subset of its domain. |
| 392: | \(C(LO,LO)\): Every linearly ordered set of linearly orderable sets has a choice function. |
| 394: | \(C(WO,LO)\): Every well ordered set of non-empty linearly orderable sets has a choice function. |
| 337: | \(C(WO\), uniformly linearly ordered): If \(X\) is a well ordered collection of non-empty sets and there is a function \(f\) defined on \(X\) such that for every \(x\in X\), \(f(x)\) is a linear ordering of \(x\), then there is a choice function for \(X\). |
| 92: | \(C(WO,{\Bbb R})\): Every well ordered family of non-empty subsets of \({\Bbb R}\) has a choice function. |
| 170: | \(\aleph_{1}\le 2^{\aleph_{0}}\). |
| 93: | There is a non-measurable subset of \({\Bbb R}\). |
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