We have the following indirect implication of form equivalence classes:
| Implication | Reference |
|---|---|
| 40 \(\Rightarrow\) 39 | clear |
| 39 \(\Rightarrow\) 8 | clear |
| 8 \(\Rightarrow\) 27 | clear |
| 27 \(\Rightarrow\) 31 | clear |
| 31 \(\Rightarrow\) 34 | clear |
| 34 \(\Rightarrow\) 104 | clear |
Here are the links and statements of the form equivalence classes referenced above:
| Howard-Rubin Number | Statement |
|---|---|
| 40: | \(C(WO,\infty)\): Every well orderable set of non-empty sets has a choice function. Moore, G. [1982], p 325. |
| 39: | \(C(\aleph_{1},\infty)\): Every set \(A\) of non-empty sets such that \(\vert A\vert = \aleph_{1}\) has a choice function. Moore, G. [1982], p. 202. |
| 8: | \(C(\aleph_{0},\infty)\): |
| 27: | \((\forall \alpha)( UT(\aleph_{0},\aleph_{\alpha}, \aleph_{\alpha}))\): The union of denumerably many sets each of power \(\aleph_{\alpha }\) has power \(\aleph_{\alpha}\). Moore, G. [1982], p 36. |
| 31: | \(UT(\aleph_{0},\aleph_{0},\aleph_{0})\): The countable union theorem: The union of a denumerable set of denumerable sets is denumerable. |
| 34: | \(\aleph_{1}\) is regular. |
| 104: | There is a regular uncountable aleph. Jech [1966b], p 165 prob 11.26. |
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