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 \(\Rightarrow\) 89 |
On cardinals and their successors, Jech, T. 1966a, Bull. Acad. Polon. Sci. S'er. Sci. Math. Astronom. Phys. |
| 89 \(\Rightarrow\) 90 | The Axiom of Choice, Jech, 1973b, page 133 |
| 90 \(\Rightarrow\) 91 | The Axiom of Choice, Jech, 1973b, page 133 |
| 91 \(\Rightarrow\) 305 | Equivalents of the Axiom of Choice II, Rubin, 1985, theorem 5.7 |
| 305 \(\Rightarrow\) 307 | 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). |
| 89: | Antichain Principle: Every partially ordered set has a maximal antichain. Jech [1973b], p 133. |
| 90: | \(LW\): Every linearly ordered set can be well ordered. Jech [1973b], p 133. |
| 91: | \(PW\): The power set of a well ordered set can be well ordered. |
| 305: | There are \(2^{\aleph_0}\) Vitali equivalence classes. (Vitali equivalence classes are equivalence classes of the real numbers under the relation \(x\equiv y\leftrightarrow(\exists q\in{\Bbb Q})(x-y=q)\).). \ac{Kanovei} \cite{1991}. |
| 307: | If \(m\) is the cardinality of the set of Vitali equivalence classes, then \(H(m) = H(2^{\aleph_0})\), where \(H\) is Hartogs aleph function and the {\it Vitali equivalence classes} are equivalence classes of the real numbers under the relation \(x\equiv y\leftrightarrow(\exists q\in {\Bbb Q})(x-y=q)\). |
Comment: