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3.4 Logical Equivalence

Sometimes two distinct sentences have exactly the same truth values in all circumstances. Such sentences are logically equivalent.

  1. $ p\rightarrow q$
  2. $ \neg p \vee q$
  3. $ \neg q \rightarrow \neg p$
  4. \begin{displaymath} \begin{array}[t]{\vert c\vert c\vert c\vert\vert c\vert c\ve... ...{\:T\:} & \mathrm{\:T\:} & \mathrm{\:T\:}\\ \hline \end{array}\end{displaymath}
  5. $ (\neg p \vee q) \Longleftrightarrow (p \rightarrow q) \Longleftrightarrow (\neg q \rightarrow \neg p)$


Jean Mark Gawron 2009-02-16