We have the following indirect implication of form equivalence classes:
| Implication | Reference |
|---|---|
| 317 \(\Rightarrow\) 14 |
Limitations on the Fraenkel-Mostowski method of independence proofs, Howard, P. 1973, J. Symbolic Logic |
| 14 \(\Rightarrow\) 63 | clear |
| 63 \(\Rightarrow\) 70 | clear |
Here are the links and statements of the form equivalence classes referenced above:
| Howard-Rubin Number | Statement |
|---|---|
| 317: | Weak Sikorski Theorem: If \(B\) is a complete, well orderable Boolean algebra and \(f\) is a homomorphism of the Boolean algebra \(A'\) into \(B\) where \(A'\) is a subalgebra of the Boolean algebra \(A\), then \(f\) can be extended to a homomorphism of \(A\) into \(B\). |
| 14: | BPI: Every Boolean algebra has a prime ideal. |
| 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. |
Comment: