We have the following indirect implication of form equivalence classes:
| Implication | Reference |
|---|---|
| 270 \(\Rightarrow\) 62 |
Restricted versions of the compactness theorem, Kolany, A. 1991, Rep. Math. Logic |
| 62 \(\Rightarrow\) 10 | clear |
| 10 \(\Rightarrow\) 80 | clear |
| 80 \(\Rightarrow\) 389 | clear |
Here are the links and statements of the form equivalence classes referenced above:
| Howard-Rubin Number | Statement |
|---|---|
| 270: | \(CT_{\hbox{fin}}\): The compactness theorem for propositional logic restricted to sets of formulas in which each variable occurs only in a finite number of formulas. |
| 62: | \(C(\infty,< \aleph_{0})\): Every set of non-empty finite sets has a choice function. |
| 10: | \(C(\aleph_{0},< \aleph_{0})\): Every denumerable family of non-empty finite sets has a choice function. |
| 80: | \(C(\aleph_{0},2)\): Every denumerable set of pairs has a choice function. |
| 389: | \(C(\aleph_0,2,\cal P({\Bbb R}))\): Every denumerable family of two element subsets of \(\cal P({\Bbb R})\) has a choice function. \ac{Keremedis} \cite{1999b}. |
Comment: