\begin{definition}[Definition:Logical NOR/Truth Table]
The characteristic truth table of the logical NOR operator $p \downarrow q$ is as follows:
:$\begin {array} {|cc||c|} \hline
p & q & p \downarrow q \\
\hline
\F & \F & \T \\
\F & \T & \F \\
\T & \F & \F \\
\T & \T & \F \\
\hline
\end {array}$
\end{definition}