Axiom Of Choice

We have the following indirect implication of form equivalence classes:

87-alpha \(\Rightarrow\) 71-alpha given by the following sequence of implications, with a reference to its direct proof:

Implication	Reference
87-alpha \(\Rightarrow\) 71-alpha	The interdependence of certain consequences of the axiom of choice, Levy, A. 1964, Fund. Math. The Axiom of Choice, Jech, 1973b, page 120 theorem 8.1 note-9

Here are the links and statements of the form equivalence classes referenced above:

Howard-Rubin Number	Statement
87-alpha:	\(DC(\aleph_{\alpha})\): Given a relation \(R\) such that for every subset \(Y\) of a set \(X\) with \(\|Y\|<\aleph_{\alpha}\), there is an \(x\in X\) with \(Y\mathrel R x\) then there is a function \(f:\aleph_{\alpha}\to X\) such that (\(\forall\beta < \aleph_{\alpha}\)) \(\{f(\gamma): \gamma < \beta\}\mathrel R f(\beta)\).
71-alpha:	\(W_{\aleph_{\alpha}}\): \((\forall x)(\|x\|\le\aleph_{\alpha }\) or \(\|x\|\ge \aleph_{\alpha})\). Jech [1973b], page 119.

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