We have the following indirect implication of form equivalence classes:

8 \(\Rightarrow\) 10
given by the following sequence of implications, with a reference to its direct proof:

Implication Reference
8 \(\Rightarrow\) 9 Was sind und was sollen die Zollen?, Dedekind, [1888]
9 \(\Rightarrow\) 10 Zermelo's Axiom of Choice, Moore, 1982, 322

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

Howard-Rubin Number Statement
8:

\(C(\aleph_{0},\infty)\):

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.

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