Question

Which of the following is an example of inherent ambiguous language?

(a) {a^n|n>1}

(b) {a^nb^nc^md^m| n,m > 0}

(c) {0^n1^n|n>0}

(d) None of the mentioned

I got this question by my college director while I was bunking the class.

This interesting question is from Ambiguous Grammar in chapter Context Free Grammars and Languages of Automata Theory

Answer 1

The correct choice is (b) {a^nb^nc^md^m| n,m > 0}

To explain I would say: This set is context-free, since the union of two context-free languages is always context free.