Problem 1

List three strings over the alphabet {a,b,c} that are accepted by the following machine:

... and list three strings that are not accepted. Note: each of the strings you give me should contain all three characters from the alphabet - i.e. don't give me something like aaa.

Problem 2

Give a concise description in English of the language over {a,b,c} accepted by the machine from Problem 1. Notice, I'm asking you to describe the language, not the machine or how it process strings. Hint: a string is in this language if something special happens after every occurrence of one particular character.

Problem 3

Does the machine from Problem 1 accept λ, i.e. the empty string? How can you easily identify whether or not a finite automaton accepts the empty string?

Problem 4

What language does the machine below accept? L = _____________________

Problem 4

Get JFLAP up and running on your PC (helpful info). Using JFLAP, create a machine that accepts exactly the strings over alphabet {a,b,c} that start with a and end with c, and which have even length. Test it with JFLAP, print it out, and submit the printout with this homework. You can print from JFLAP or you can use screen captures, whichever you want. Note: This is the last problem from the in-class exercises.