We have the following indirect implication of form equivalence classes:
Implication | Reference |
---|---|
85 \(\Rightarrow\) 62 | clear |
62 \(\Rightarrow\) 61 | clear |
61 \(\Rightarrow\) 45-n | clear |
45-n \(\Rightarrow\) 64 |
Classes of Dedekind finite cardinals, Truss, J. K. 1974a, Fund. Math. |
64 \(\Rightarrow\) 127 |
Amorphe Potenzen kompakter Raume, Brunner, N. 1984b, Arch. Math. Logik Grundlagenforschung |
Here are the links and statements of the form equivalence classes referenced above:
Howard-Rubin Number | Statement |
---|---|
85: | \(C(\infty,\aleph_{0})\): Every family of denumerable sets has a choice function. Jech [1973b] p 115 prob 7.13. |
62: | \(C(\infty,< \aleph_{0})\): Every set of non-empty finite sets has a choice function. |
61: | \((\forall n\in\omega, n\ge 2\))\((C(\infty,n))\): For each \(n\in\omega\), \(n\ge 2\), every set of \(n\) element sets has a choice function. |
45-n: | If \(n\in\omega-\{0,1\}\), \(C(\infty,n)\): Every set of \(n\)-element sets has a choice function. |
64: | \(E(I,Ia)\) There are no amorphous sets. (Equivalently, every infinite set is the union of two disjoint infinite sets.) |
127: | An amorphous power of a compact \(T_2\) space, which as a set is well orderable, is well orderable. |
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