1. CST229 Week 4 Questions or concerns? Test#1 next Thursday Homework #3 due Hand back Homework #2 Reading: Chapters 5 & 7 In-Class Exercise #4a Chapter 5 – Machine to recognize languages In-Class Exercise#4b Test#1

2. In-Class Exercise #4a Construct regular expressions for these languages over  = {a, b}: a.L = {a n b m | n+m is even} b.L = {w | |w| mod 3 = 0} c.L = { w | number of b’s in w is divisible by 5}

3. Regular Expressions Construct regular expressions for these: L1 = {a 1 b 1 } L2 = {a 2 b 2 } L3 = {a 3 b 3 } L6 = {a 6 b 6 } Ln = {a n | n ≥ 0} Lnm = {a n b m | n, m ≥ 0} Ldoublen = {a n b n | n ≥ 0 }

4. CST229 Week 4 Questions or concern? Test#1 next Thursday Homework #3 due Hand back Homework #2 Reading: Chapters 5 & 7 In-Class Exercise #4a Chapter 5 – Machine to recognize languages In-Class Exercise#4b What’s going to be on the test

5. In-Class Exercise #4b Construct Finite Automata for these languages a.L = {a n b m | n+m is even} b.L = {w | |w| mod 3 = 0} c.L = { w | number of b’s in w is divisible by 5} d.L = { w | w contains even number of a’s and even number of b’s}

6. Finite Automata Construct FAs for these: L1 = {a 1 b 1 } L2 = {a 2 b 2 } L3 = {a 3 b 3 } L6 = {a 6 b 6 } Ln = {a n | n ≥ 0} Lnm = {a n b m | n, m ≥ 0} Ldoublen = {a n b n | n ≥ 0 }

7. Next Thursday 2/6 First hour – Talk about Lab#1 – Last minute questions about the test Second hour ++ – Test#1 Covers Homeworks #1 - #3 – Set theory – Permutations / Combinations – Chapter 2 problems – Chapter 3 problems – Chapter 4 problems Open notes / Open book