We have the following indirect implication of form equivalence classes:
Implication | Reference |
---|---|
15 \(\Rightarrow\) 30 | The Axiom of Choice, Jech, 1973b, page 53 problem 4.12 |
30 \(\Rightarrow\) 62 | clear |
62 \(\Rightarrow\) 61 | clear |
61 \(\Rightarrow\) 88 | clear |
88 \(\Rightarrow\) 268 |
Subalgebra lattices of unary algebras and an axiom of choice, Lampe, W. A. 1974, Colloq. Math. |
268 \(\Rightarrow\) 269 |
Subalgebra lattices of unary algebras and an axiom of choice, Lampe, W. A. 1974, Colloq. Math. |
Here are the links and statements of the form equivalence classes referenced above:
Howard-Rubin Number | Statement |
---|---|
15: | \(KW(\infty,\infty)\) (KW), The Kinna-Wagner Selection Principle: For every set \(M\) there is a function \(f\) such that for all \(A\in M\), if \(|A|>1\) then \(\emptyset\neq f(A)\subsetneq A\). (See Form 81(\(n\)). |
30: | Ordering Principle: Every set can be linearly ordered. |
62: | \(C(\infty,< \aleph_{0})\): Every set of non-empty finite sets has a choice function. |
61: | \((\forall n\in\omega, n\ge 2\))\((C(\infty,n))\): For each \(n\in\omega\), \(n\ge 2\), every set of \(n\) element sets has a choice function. |
88: | \(C(\infty ,2)\): Every family of pairs has a choice function. |
268: | If \({\cal L}\) is a lattice isomorphic to the lattice of subalgebras of some unary universal algebra (a unary universal algebra is one with only unary or nullary operations) and \(\alpha \) is an automorphism of \({\cal L}\) of order 2 (that is, \(\alpha ^{2}\) is the identity) then there is a unary algebra \(\frak A\) and an isomorphism \(\rho \) from \({\cal L}\) onto the lattice of subalgebras of \(\frak A^{2}\) with \[\rho(\alpha(x))=(\rho(x))^{-1} (= \{(s,t) : (t,s)\in\rho(x)\})\] for all \(x\in {\cal L}\). |
269: | For every cardinal \(m\), there is a set \(A\) such that \(2^{|A|^2}\ge m\) and there is a choice function on the collection of 2-element subsets of \(A\). |
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