We have the following indirect implication of form equivalence classes:
			
| Implication | Reference | 
|---|---|
| 9 \(\Rightarrow\) 10 | Zermelo's Axiom of Choice, Moore, 1982, 322 | 
| 10 \(\Rightarrow\) 249 | 
Here are the links and statements of the form equivalence classes referenced above:
| Howard-Rubin Number | Statement | 
|---|---|
| 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. | 
| 249: | If \(T\) is an infinite tree in which every element has exactly 2 immediate successors then \(T\) has an infinite branch. | 
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