We have the following indirect implication of form equivalence classes:
| Implication | Reference |
|---|---|
| 424 \(\Rightarrow\) 94 |
On first and second countable spaces and the axiom of choice, Gutierres, G 2004, Topology and its Applications. |
| 94 \(\Rightarrow\) 34 |
Non-constructive properties of the real numbers, Howard, P. 2001, Math. Logic Quart. |
| 34 \(\Rightarrow\) 104 | clear |
| 104 \(\Rightarrow\) 182 | clear |
Here are the links and statements of the form equivalence classes referenced above:
| Howard-Rubin Number | Statement |
|---|---|
| 424: | Every Lindel\"{o}f metric space is super second countable. \ac{Gutierres} \cite{2004} and note 159. \iput{super second countable} |
| 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. |
| 34: | \(\aleph_{1}\) is regular. |
| 104: | There is a regular uncountable aleph. Jech [1966b], p 165 prob 11.26. |
| 182: | There is an aleph whose cofinality is greater than \(\aleph_{0}\). |
Comment: