We have the following indirect implication of form equivalence classes:
| Implication | Reference |
|---|---|
| 133 \(\Rightarrow\) 63 |
Dedekind-Endlichkeit und Wohlordenbarkeit, Brunner, N. 1982a, Monatsh. Math. |
| 63 \(\Rightarrow\) 70 | clear |
| 70 \(\Rightarrow\) 142 | The Axiom of Choice, Jech, 1973b, page 7 problem 11 |
Here are the links and statements of the form equivalence classes referenced above:
| Howard-Rubin Number | Statement |
|---|---|
| 133: | Every set is either well orderable or has an infinite amorphous subset. |
| 63: |
\(SPI\): Weak ultrafilter principle: Every infinite set has a non-trivial ultrafilter.
|
| 70: | There is a non-trivial ultrafilter on \(\omega\). Jech [1973b], prob 5.24. |
| 142: | \(\neg PB\): There is a set of reals without the property of Baire. Jech [1973b], p. 7. |
Comment: