Double Negation/Double Negation Elimination/Sequent Form/Formulation 1

Theorem
If we can conclude $\neg \neg p$, then we may infer $p$:


 * $\neg \neg p \vdash p$

It can be written:
 * $\displaystyle {\neg \neg p \over p} \neg \neg_e$

This is called the Law of Double Negation Elimination.

Its abbreviation in a tableau proof is $\neg \neg \mathcal E$.

This rule requires acceptance of the Law of the Excluded Middle, to which it is logically equivalent.

Also see

 * Double Negation Elimination implies Law of Excluded Middle