Axim 3.10 (Power set axiom). Let \(X\) and \(Y\) be sets. Then there exists a set, denoted \(Y^X\), which consists of all the functions from \(X\) to \(Y\), thus $$ f\in Y^X\iff (f\text{ is a function with domain }X\text{ and range }Y) $$
Axim 3.10 (Power set axiom). Let \(X\) and \(Y\) be sets. Then there exists a set, denoted \(Y^X\), which consists of all the functions from \(X\) to \(Y\), thus $$ f\in Y^X\iff (f\text{ is a function with domain }X\text{ and range }Y) $$