We have the following indirect implication of form equivalence classes:
| Implication | Reference |
|---|---|
| 91 \(\Rightarrow\) 79 | clear |
| 79 \(\Rightarrow\) 94 | clear |
| 94 \(\Rightarrow\) 35 |
Non-constructive properties of the real numbers, Howard, P. 2001, Math. Logic Quart. |
Here are the links and statements of the form equivalence classes referenced above:
| Howard-Rubin Number | Statement |
|---|---|
| 91: | \(PW\): The power set of a well ordered set can be well ordered. |
| 79: | \({\Bbb R}\) can be well ordered. Hilbert [1900], p 263. |
| 94: | \(C(\aleph_{0},\infty,{\Bbb R})\): Every denumerable family of non-empty sets of reals has a choice function. Jech [1973b], p 148 prob 10.1. |
| 35: | The union of countably many meager subsets of \({\Bbb R}\) is meager. (Meager sets are the same as sets of the first category.) Jech [1973b] p 7 prob 1.7. |
Comment: