Cartesian Product.
Given sets \(A\) and \(B\text{,}\) we can form the set
\begin{equation*}
A \times B = \{(x,y) \st x \in A \wedge y \in B\}
\end{equation*}
to be the set of all ordered pairs \((x,y)\) where \(x\) is an element of \(A\) and \(y\) is an element of \(B\text{.}\) We call \(A \times B\) the Cartesian product of \(A\) and \(B\text{.}\)