(double negative elimination)

Double negative elimination is a theorem of classical logic, but not of weaker logics such as intuitionistic logic and minimal logic.

Converting a formula to DNF involves using logical equivalences, such as the double negative elimination, De Morgan's laws, and the distributive law.

The principle of double negative elimination ((α ) ) α is comparable to a variant of call-cc which expects its argument f to always evaluate the current continuation without normally returning a value.

In propositional logic, double negative elimination (also called double negation elimination, double negative introduction, double negation introduction, or simply double negation) are two valid rules of replacement.