We have the following indirect implication of form equivalence classes:
Implication | Reference |
---|---|
407 \(\Rightarrow\) 14 |
Effective equivalents of the Rasiowa-Sikorski lemma, Bacsich, P. D. 1972b, J. London Math. Soc. Ser. 2. |
14 \(\Rightarrow\) 49 |
A survey of recent results in set theory, Mathias, A.R.D. 1979, Period. Math. Hungar. |
49 \(\Rightarrow\) 326 | Logic at Work: Essay Dedicated to the Memory of Helen Rasiowa, Wojtylak, 1999, |
Here are the links and statements of the form equivalence classes referenced above:
Howard-Rubin Number | Statement |
---|---|
407: | Let \(B\) be a Boolean algebra, \(b\) a non-zero element of \(B\) and \(\{A_i: i\in\omega\}\) a sequence of subsets of \(B\) such that for each \(i\in\omega\), \(A_i\) has a supremum \(a_i\). Then there exists an ultrafilter \(D\) in \(B\) such that \(b\in D\) and, for each \(i\in\omega\), if \(a_i\in D\), then \(D\cap\ A_i\neq\emptyset\). |
14: | BPI: Every Boolean algebra has a prime ideal. |
49: | Order Extension Principle: Every partial ordering can be extended to a linear ordering. Tarski [1924], p 78. |
326: | 2-SAT: Restricted Compactness Theorem for Propositional Logic III: If \(\Sigma\) is a set of formulas in a propositional language such that every finite subset of \(\Sigma\) is satisfiable and if every formula in \(\Sigma\) is a disjunction of at most two literals, then \(\Sigma\) is satisfiable. (A literal is a propositional variable or its negation.) Wojtylak [1999] (listed as Wojtylak [1995]) |
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