效绵鼎 CFG Formalism Terminals symbols of the alphabet of the language being defined Variables nonterminals a finite set of other symbols,each of which represents a language. Start symbol the variable whose language is the one being defined 7CFG Formalism ◼ Terminals = symbols of the alphabet of the language being defined. ◼ Variables = nonterminals = a finite set of other symbols, each of which represents a language. ◼ Start symbol = the variable whose language is the one being defined. 7