Exercise 4.1.1: Prove that the following are not regular languages. a) ( 01 n This language, consisting of a string of O's followed by an equal-length string of 1's, is the language Loi we considered informally at the beginning of the section. Here, you should apply the pumping lemma in the proof. ar- acters and ") that can appear in a well-formed arithmetic expression. * c) f0"10" I n1 d) o2 n and m are arbitrary integers)