A joined property of the statements \(P\) and \(Q\), read
| “\(P\) excludes \(Q\)”, | |
| or | “\(P\) precludes \(Q\)”, |
| or | “\(P\) contradicts \(Q\)”, |
\(P\) and \(Q\) cannot be ‘true’ at the same time,
which means that
\[\begin{equation*}
\lnot (P \land Q)
\end{equation*}
\]
is a tautology.