\begin{definition}[Definition:Operation/Binary Operation/Infix Notation]
Let $\circ: S \times T \to U$ be a binary operation.
When $\circ \left ({x, y}\right) = z$, it is common to put the symbol for the operation between the two operands:
: $z = x \circ y$
This convention is called '''infix notation'''.
\end{definition}