CS 321: Homework 1

Due date: October 8, 2008

Section 1.2: 6, 7

Additional Problem:

   Describe via an English sentence each of the languages from the
   following Exercises in Section 1.2.

   14b, 15a, 18b, 18d

Section 2.1: 2(d), 7(c), 9(c), 12, 17 (see hint 1 below) 

Hint 1: We know that L is regular. Thus there is a DFA M such that
        L=L(M). To solve this problem you need to describe how to form
        a new DFA M' from M such that L(M')=L-{\lambda}. You can
        construct such an M' by adding a single state to M with the
        appropriate arcs. You need to provide an informal argument as
        to why your construction is correct.