47) A grammar that produces more than one parse tree for some sentence is called

48) Given a grammar G a production of G with a dot at some position of the right side is called

49) If a language is denoted by a regular expression L = ( x )* (x | y x ) , then which of the following is not a legal string within L ?

50) If every string of a language can be determined, whether it is legal or illegal in finite time, the language is called

51) The defining language for developing a formalism in which language definitions can be stated, is called