in boolean logic formula conjunctive normal form CNF clausal normal form conjunction clause clause disjunction literal cite httpsenwikipediaorgwikiconjunctive_normal_formin word CNF formula type represent logical and conjunction represent logical or disjunction vij boolean variable negation each statement bracket call clause vij call literalsyou give CNF contain variable x1xm negation we know variable occur clause negation negation total your task determine CNF satisfiable value variable CNF value true if CNF satisfiable need determine value variable CNF true it guarantee variable occur clause