CS4311: Introduction to Computation Theory hw6
CS 4311 Introduction to Computation Theory
Homework 7: Chapter 2
Due: Wednesday, 10/25/06, beginning of class
(Assigned: Wednesday, 10/19/06)
You are required to turn in answers to all the questions. However, only a random
subset of the questions will be graded.
While discussion with others is permitted and encouraged, the final work
should be done individually. You are not allowed
to work in groups.
The answers, comments, and programs (if any) must be the original
work of the author.
You are allowed to build on material supplied in the class. If you use
any other source than the current class notes and the textbook, specify it
clearly.
1. (Similar to exercise 2.30b) Use the pumping lemma to show that the
following language is not context free.
First do the proof with a string of your choice and then do a proof
where the string s is 0q#02q#04q where
q is p/2 (half of the pumping length).
2. (Exercise 2.30d) Use the pumping lemma to show that the
following language is not context free.
{t1#t2# ... #tk| k ≥ 2, each
ti∈ {a,b}*, and ti = tj for some i
≠ j}