Disjunctive normal form
A propositional formula of the form
where each (; ) is either a variable or the negation of a variable. The form (*) is realizable if and only if, for each , do not contain both the formulas and , where is any variable. For any propositional formula it is possible to construct an equivalent disjunctive normal form containing the same variables as . Such a formula is then said to be the disjunctive normal form of the formula .
Disjunctive normal form. Encyclopedia of Mathematics. URL: http://www.encyclopediaofmath.org/index.php?title=Disjunctive_normal_form&oldid=14566