Choice function
= Choice function
{wiki}
A choice function on a family $\mathcal A$ of nonempty sets is a function $f$ with $f(A)\in A$ for every $A\in\mathcal A$.
= Choice function
{wiki}
A choice function on a family $\mathcal A$ of nonempty sets is a function $f$ with $f(A)\in A$ for every $A\in\mathcal A$.