example of tautology
ExampleOfTautology
2005-08-11 19:43:54
2005-08-11 19:43:54
Example
tautology
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An example of a tautology and how to test it is given in the truth table below for the statement $(P \vee Q) \vee ( \neg P \wedge \neg Q) $
\begin{center}
\begin{tabular}{ccccc}
$P$ & $Q$ & $\neg P \wedge \neg Q$ & $P \vee Q$ & $(P \vee Q) \vee ( \neg P \wedge \neg Q)$ \\
\hline
F & F & T & F & T \\
F & T & F & T & T \\
T & F & F & T & T \\
T & T & F & T & T
\end{tabular}
\end{center}
Thus for whatever truth values P and Q take on, the statement always comes out true as shown in the last coloumn of the truth table.