We have the following indirect implication of form equivalence classes:
| Implication | Reference |
|---|---|
| 88 \(\Rightarrow\) 80 | clear |
| 80 \(\Rightarrow\) 18 | clear |
Here are the links and statements of the form equivalence classes referenced above:
| Howard-Rubin Number | Statement |
|---|---|
| 88: | \(C(\infty ,2)\): Every family of pairs has a choice function. |
| 80: | \(C(\aleph_{0},2)\): Every denumerable set of pairs has a choice function. |
| 18: | \(PUT(\aleph_{0},2,\aleph_{0})\): The union of a denumerable family of pairwise disjoint pairs has a denumerable subset. |
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