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 \(\Rightarrow\) 144 |
Axioms of multiple choice, Levy, A. 1962, Fund. Math. |
| 144 \(\Rightarrow\) 416 |
Constructive order theory, Ern'e, M. 2001, Math. Logic Quart. |
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). |
| 144: | Every set is almost well orderable. |
| 416: | Every non-compact topological space \(S\) is the union of a set that is well-ordered by inclusion and consists of open proper subsets of \(S\). |
Comment: