We have the following indirect implication of form equivalence classes:
Implication | Reference |
---|---|
2 \(\Rightarrow\) 3 |
On successors in cardinal arithmetic, Truss, J. K. 1973c, Fund. Math. |
3 \(\Rightarrow\) 9 |
Cardinal addition and the axiom of choice, Howard, P. 1974, Bull. Amer. Math. Soc. |
9 \(\Rightarrow\) 10 | Zermelo's Axiom of Choice, Moore, 1982, 322 |
10 \(\Rightarrow\) 288-n | clear |
288-n \(\Rightarrow\) 373-n | clear |
Here are the links and statements of the form equivalence classes referenced above:
Howard-Rubin Number | Statement |
---|---|
2: | Existence of successor cardinals: For every cardinal \(m\) there is a cardinal \(n\) such that \(m < n\) and \((\forall p < n)(p \le m)\). |
3: | \(2m = m\): For all infinite cardinals \(m\), \(2m = m\). |
9: | Finite \(\Leftrightarrow\) Dedekind finite: \(W_{\aleph_{0}}\) Jech [1973b]: \(E(I,IV)\) Howard/Yorke [1989]): Every Dedekind finite set is finite. |
10: | \(C(\aleph_{0},< \aleph_{0})\): Every denumerable family of non-empty finite sets has a choice function. |
288-n: | If \(n\in\omega-\{0,1\}\), \(C(\aleph_0,n)\): Every denumerable set of \(n\)-element sets has a choice function. |
373-n: | (For \(n\in\omega\), \(n\ge 2\).) \(PC(\aleph_0,n,\infty)\): Every denumerable set of \(n\)-element sets has an infinite subset with a choice function. |
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