Negational normal form

Negative normal form is way to represent the formula by keeping the negation symbol only to the literals.

If α and φ are boolean formulas, then α$\wedge$φ , α$\vee$φ, $\neg$α, α$\rightarrow$φ are all boolean formulas. The boolean formulas are made up of literals which are propositional atoms. A formula can be converted to the NNF by simply moving the negations across braces either using De Morgan's laws or the property that $\neg\neg$α is α itself.

External links

• Math logic tutor