A binary logical connective, denoted
\[\begin{equation*}
P \neq Q
\quad \text{or} \quad
P \oplus Q
\end{equation*}
\]
and read
that is ‘true’ if and only if
which is equivalent to
\[\begin{equation*}
(P \land \lnot Q) \lor (\lnot P \land Q).
\end{equation*}
\]