We have the following indirect implication of form equivalence classes:
| Implication | Reference |
|---|---|
| 391 \(\Rightarrow\) 112 | clear |
| 112 \(\Rightarrow\) 90 | Equivalents of the Axiom of Choice II, Rubin/Rubin, 1985, page 79 |
| 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 |
|---|---|
| 391: | \(C(\infty,LO)\): Every set of non-empty linearly orderable sets has a choice function. |
| 112: | \(MC(\infty,LO)\): For every family \(X\) of non-empty sets each of which can be linearly ordered there is a function \(f\) such that for all \(y\in X\), \(f(y)\) is a non-empty finite subset of \(y\). |
| 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 \(x\equiv y\leftrightarrow(\exists q\in {\Bbb Q})(x-y=q)\). |
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