Double Negation/Double Negation Introduction
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Proof Rule
The rule of double negation introduction is a valid argument in types of logic dealing with negation $\neg$.
This includes propositional logic and predicate logic, and in particular natural deduction.
Proof Rule
- If we can conclude $\phi$, then we may infer $\neg \neg \phi$.
Sequent Form
- $p \vdash \neg \neg p$