We have the following indirect implication of form equivalence classes:
| Implication | Reference |
|---|---|
| 165 \(\Rightarrow\) 122 | clear |
| 122 \(\Rightarrow\) 250 | clear |
| 250 \(\Rightarrow\) 111 | clear |
Here are the links and statements of the form equivalence classes referenced above:
| Howard-Rubin Number | Statement |
|---|---|
| 165: | \(C(WO,WO)\): Every well ordered family of non-empty, well orderable sets has a choice function. |
| 122: | \(C(WO,<\aleph_{0})\): Every well ordered set of non-empty finite sets has a choice function. |
| 250: | \((\forall n\in\omega-\{0,1\})(C(WO,n))\): For every natural number \(n\ge 2\), every well ordered family of \(n\) element sets has a choice function. |
| 111: | \(UT(WO,2,WO)\): The union of an infinite well ordered set of 2-element sets is an infinite well ordered set. |
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