Conjunctive grammars are a class of formal grammarsstudied in formal language theory.They extend the basic type of grammars,the context-free grammars,with a conjunction operation.Besides explicit conjunction,conjunctive grammars allow implicit disjunctionrepresented by multiple rules for a single nonterminal symbol,which is the only logical connective expressible in context-free grammars.Conjunction can be used, in particular,to specify intersection of languages.A further extension of conjunctive grammarsknown as Boolean grammarsadditionally allows explicit negation.
Conjunctive grammars are a class of formal grammarsstudied in formal language theory.They extend the basic type of grammars,the context-free grammars,with a conjunction operation.Besides explicit conjunction,conjunctive grammars allow implicit disjunctionrepresented by multiple rules for a single nonterminal symbol,which is the only logical connective expressible in context-free grammars.Conjunction can be used, in particular,to specify intersection of languages.A further extension of conjunctive grammarsknown as Boolean grammarsadditionally allows explicit negation. The rules of a conjunctive grammar are of the form where is a nonterminal and, ..., are strings formed of symbols in and (finite sets of terminal and nonterminal symbols respectively).Informally, such a rule asserts that every string over that satisfies each of the syntactical conditions representedby , ..., therefore satisfies the condition defined by . (en)
Conjunctive grammars are a class of formal grammarsstudied in formal language theory.They extend the basic type of grammars,the context-free grammars,with a conjunction operation.Besides explicit conjunction,conjunctive grammars allow implicit disjunctionrepresented by multiple rules for a single nonterminal symbol,which is the only logical connective expressible in context-free grammars.Conjunction can be used, in particular,to specify intersection of languages.A further extension of conjunctive grammarsknown as Boolean grammarsadditionally allows explicit negation. (en)
