We have the following indirect implication of form equivalence classes:
			
| Implication | Reference | 
|---|---|
| 149 \(\Rightarrow\) 67 | The axiom of choice in topology, Brunner,  N. 1983d, Notre Dame J. Formal Logic note-26 | 
| 67 \(\Rightarrow\) 89 | On cardinals and their successors, Jech,  T. 1966a, Bull. Acad. Polon. Sci. S'er. Sci. Math. Astronom. Phys. | 
| 89 \(\Rightarrow\) 90 | The Axiom of Choice, Jech, 1973b, page 133 | 
| 90 \(\Rightarrow\) 91 | The Axiom of Choice, Jech, 1973b, page 133 | 
| 91 \(\Rightarrow\) 79 | clear | 
| 79 \(\Rightarrow\) 367 | Eine Basis aller Zahlen und die unstetigen Losungen der Functionalgleichung: \(f(x+y) = f(x) + f(y)\), Hamel, G. 1905, Math. Ann. | 
| 367 \(\Rightarrow\) 366 | Eine Basis aller Zahlen und die unstetigen Losungen der Functionalgleichung: \(f(x+y) = f(x) + f(y)\), Hamel, G. 1905, Math. Ann. | 
Here are the links and statements of the form equivalence classes referenced above:
| Howard-Rubin Number | Statement | 
|---|---|
| 149: | \(A(F)\): Every \(T_2\) topological space is a continuous, finite to one image of an \(A1\) space. | 
| 67: | \(MC(\infty,\infty)\) \((MC)\), The Axiom of Multiple Choice: For every set \(M\) of non-empty sets there is a function \(f\) such that \((\forall x\in M)(\emptyset\neq f(x)\subseteq x\) and \(f(x)\) is finite). | 
| 89: | Antichain Principle: Every partially ordered set has a maximal antichain. Jech [1973b], p 133. | 
| 90: | \(LW\): Every linearly ordered set can be well ordered. Jech [1973b], p 133. | 
| 91: | \(PW\): The power set of a well ordered set can be well ordered. | 
| 79: | \({\Bbb R}\) can be well ordered. Hilbert [1900], p 263. | 
| 367: | There is a Hamel basis for \(\Bbb R\) as a vector space over \(\Bbb Q\). | 
| 366: | There is a discontinuous function \(f: \Bbb R \to\Bbb R\) such that for all real \(x\) and \(y\), \(f(x+y)=f(x)+f(y)\). | 
Comment: