\begin{definition}[Definition:Dual Relation/Complement of Inverse]
Let $\RR \subseteq S \times T$ be a binary relation.
Then the '''dual''' of $\RR$ is denoted $\RR^d$ and is defined as:
:$\RR^d := \overline {\paren {\RR^{-1} } }$
where:
:$\RR^{-1}$ denotes the inverse of $\RR$
:$\overline {\paren {\RR^{-1} } }$ denotes the complement of the inverse of $\RR$.
Category:Definitions/Relation Theory
\end{definition}