COS 550 F07 HW #9 DUE Thursday 11/20/08
NDFA Simulator,         20 points
p.258 Problem  2,       30 points
p.265 Problem  2,       10 points
p.265 Problem  6(a),     5 points
p.265 Problem 10,       15 points
ASSOC. PROBLEM below,   20 points
********** Problem Notes *********,
NDFA Simulator. Write a NDFA simulator. The easiest way to do this is to 
start with your DFA simulator and modify it to get an NDFA simulator.

ASSOCIATIVITY PROBLEM: Give a non-deterministic finite automaton that 
accepts all strings over the alphabet {a, b, c} that have the same value 
when evaluated left to right as right to left using the following table:

       a b c
      -------
   a | a a c
   b | c a b
   c | b c a

For example, abc evaluated left-to-right gives ac which gives c. abc 
evaluated right to left gives ab which gives a. Thus, your machine must 
reject abc. On the other hand, aaa gives a regardless of the direction 
that you use. Thus, your machine must accept aaa. Be sure to run your 
solution on the NDFA simulator you wrote as the first exercise for this 
problem set. Submit sample runs of your solution with the homework.