We have the following indirect implication of form equivalence classes:
| Implication | Reference |
|---|---|
| 15 \(\Rightarrow\) 30 | The Axiom of Choice, Jech, 1973b, page 53 problem 4.12 |
| 30 \(\Rightarrow\) 10 | clear |
| 10 \(\Rightarrow\) 80 | clear |
Here are the links and statements of the form equivalence classes referenced above:
| Howard-Rubin Number | Statement |
|---|---|
| 15: | \(KW(\infty,\infty)\) (KW), The Kinna-Wagner Selection Principle: For every set \(M\) there is a function \(f\) such that for all \(A\in M\), if \(|A|>1\) then \(\emptyset\neq f(A)\subsetneq A\). (See Form 81(\(n\)). |
| 30: | Ordering Principle: Every set can be linearly ordered. |
| 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. |
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