Principle of Non-Contradiction/Proof Rule/Tableau Form
Proof Rule
Let $\phi$ be a well-formed formula in a tableau proof.
The Principle of Non-Contradiction is invoked for $\phi$ and $\neg \phi$ in the following manner:
| Pool: | The pooled assumptions of $\phi$ | ||||||||
| The pooled assumptions of $\neg \phi$ | |||||||||
| Formula: | $\bot$ | ||||||||
| Description: | Principle of Non-Contradiction | ||||||||
| Depends on: | The line containing the instance of $\phi$ | ||||||||
| The line containing the instance of $\neg \phi$ | |||||||||
| Abbreviation: | $\operatorname {PNC}$ or $\neg \EE$ |