We have the following indirect implication of form equivalence classes:
			
| Implication | Reference | 
|---|---|
| 214 \(\Rightarrow\) 9 | clear | 
| 9 \(\Rightarrow\) 13 | clear | 
Here are the links and statements of the form equivalence classes referenced above:
| Howard-Rubin Number | Statement | 
|---|---|
| 214: | \(Z(\omega)\): For every family \(A\) of infinite sets, there is a function \(f\) such that for all \(y\in A\), \(f(y)\) is a non-empty subset of \(y\) and \(|f(y)|=\aleph_{0}\). | 
| 9: | Finite \(\Leftrightarrow\) Dedekind finite: \(W_{\aleph_{0}}\) Jech [1973b]: \(E(I,IV)\) Howard/Yorke [1989]): Every Dedekind finite set is finite. | 
| 13: | Every Dedekind finite subset of \({\Bbb R}\) is finite. | 
Comment: