Conjunctive normal form

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A propositional formula of the form


where each , ; , is either an atomic formula (a variable or constant) or the negation of an atomic formula. The conjunctive normal form (*) is a tautology if and only if for any one can find both formulas and among the , for some atomic formula . Given any propositional formula , one can construct a conjunctive normal form equivalent to it and containing the same variables and constants as . This is called the conjunctive normal form of .


The dual of a conjunctive normal form is a disjunctive normal form. Both are also used in the theory of Boolean functions (cf. Boolean functions, normal forms of).

How to Cite This Entry:
Conjunctive normal form. S.K. Sobolev (originator), Encyclopedia of Mathematics. URL:
This text originally appeared in Encyclopedia of Mathematics - ISBN 1402006098