Axiom Of Choice

We have the following indirect implication of form equivalence classes:

89 \(\Rightarrow\) 137-k given by the following sequence of implications, with a reference to its direct proof:

Implication	Reference
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 \(\Rightarrow\) 139
139 \(\Rightarrow\) 137-k	Cancellation laws for surjective cardinals, Truss, J. K. 1984, Ann. Pure Appl. Logic

Here are the links and statements of the form equivalence classes referenced above:

Howard-Rubin Number	Statement
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.
139:	Using the discrete topology on 2, \(2^{\cal P(\omega)}\) is compact.
137-k:	Suppose \(k\in\omega-\{0\}\). If \(f\) is a 1-1 map from \(k\times X\) into \(k\times Y\) then there are partitions \(X = \bigcup_{i \le k} X_{i} \) and \(Y = \bigcup_{i \le k} Y_{i} \) of \(X\) and \(Y\) such that \(f\) maps \(\bigcup_{i \le k} (\{i\} \times X_{i})\) onto \(\bigcup_{i \le k} (\{i\} \times Y_{i})\).

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