The statement is:
For every family $\{S_i\}_{i \in I}$ of mutually disjoint, non-empty sets, there exists a set $S$ which contains exactly one element from each $S_i$.
I know AOC implies this, but does it work the other way around?
The statement is:
For every family $\{S_i\}_{i \in I}$ of mutually disjoint, non-empty sets, there exists a set $S$ which contains exactly one element from each $S_i$.
I know AOC implies this, but does it work the other way around?
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Let $E$ be a set of non-empty sets on which we wish to define a choice function. Then the sets $\{S\} \times S$, for $S \in E$, are disjoint and nonempty. If $f$ consists of one element of each of these sets, then the required choice function can be selected to be $f$.
(If you don't have the replacement schema, you can show that the collection of sets $\{S\} \times S$ form a set. This collection is a subset of $P[P(E \times \bigcup E)].$)