Definition:Contradictory/Branch

Definition

Let $T$ be a labeled tree for propositional logic.

Let $\Gamma$ be a branch of $T$.

Then $\Gamma$ is a contradictory branch if and only if, for some WFF of propositional logic $\mathbf A$, both $\mathbf A$ and $\neg \mathbf A$ occur along $\Gamma$.

Sources

• 1996: H. Jerome Keisler and Joel Robbin: Mathematical Logic and Computability ... (previous) ... (next): $\S 1.7$: Tableaus