Editing Choice function (section)

{{Short description|Mathematical function}}
{{for|the combinatorial choice function C(n, k)|Combination|Binomial coefficient}}

Let ''X'' be a [[set of sets]] none of which are empty. Then a '''choice function''' ('''selector''', '''selection''') on ''X'' is a [[mathematical function]] ''f'' that is defined on ''X'' such that ''f'' is a mapping that assigns each element of ''X'' to one of its elements.