A binary operation means that you are taking two things in and you are getting one thing out; for instance:

\begin{equation} f: (\mathbb{F},\mathbb{F}) \to \mathbb{F} \end{equation}

This is also closed, but binary operations dons’t have to be.

A binary operation means that you are taking two things in and you are getting one thing out; for instance:

\begin{equation} f: (\mathbb{F},\mathbb{F}) \to \mathbb{F} \end{equation}

This is also closed, but binary operations dons’t have to be.