We have the following indirect implication of form equivalence classes:
| Implication | Reference |
|---|---|
| 149 \(\Rightarrow\) 67 |
The axiom of choice in topology, Brunner, N. 1983d, Notre Dame J. Formal Logic note-26 |
| 67 \(\Rightarrow\) 76 | clear |
| 76 \(\Rightarrow\) 131 | clear |
Here are the links and statements of the form equivalence classes referenced above:
| Howard-Rubin Number | Statement |
|---|---|
| 149: | \(A(F)\): Every \(T_2\) topological space is a continuous, finite to one image of an \(A1\) space. |
| 67: | \(MC(\infty,\infty)\) \((MC)\), The Axiom of Multiple Choice: For every set \(M\) of non-empty sets there is a function \(f\) such that \((\forall x\in M)(\emptyset\neq f(x)\subseteq x\) and \(f(x)\) is finite). |
| 76: | \(MC_\omega(\infty,\infty)\) (\(\omega\)-MC): For every family \(X\) of pairwise disjoint non-empty sets, there is a function \(f\) such that for each \(x\in X\), f(x) is a non-empty countable subset of \(x\). |
| 131: | \(MC_\omega(\aleph_0,\infty)\): For every denumerable family \(X\) of pairwise disjoint non-empty sets, there is a function \(f\) such that for each \(x\in X\), f(x) is a non-empty countable subset of \(x\). |
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