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We know axiom of choice states that:

Given any collection $\{ S_i : i \in I \} $ of nonempty sets, there exists a choice function $f: I \to \bigcup_{i \in I} S_i $ such that $f(i) \in S_i $ for all $i \in I$.

Question: I am bit confused because in one books I saw the axiom of choice as: For any collection $\{ S_i : i \in I \} $ of nonempty sets, $\prod_{i \in I} S_i $ is non empty.

Why are they equivalent?

1 Answers1

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The product of a collection $\{S_i\}$ is, by definition, the collection of all choice functions $I\to \bigcup_{i\in I}S_i$.

Ittay Weiss
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