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CS 341 Automata Theory, Practice Quiz 2, Time = 8 mins.

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1. Let Σ = {}. Then Σ* is:

1. {}
2. {a}
3. {ε}
4. {b}
5. none of a - d

2. Let L = {ε, a} and let Σ = {a, b}. M = LΣ*. M is:

1. {ε, a}
2. {a, b}
3. {ε, b}
4. {a, b}*
5. none of a – d

3. Let L = {a, ε} and let Σ = {a, b}. M = Σ*L. M is:

1. {ε, a}
2. {a, b}
3. {ε, b}
4. {a, b}*
5. none of a - d

4. Let Σ be a finite alphabet such that |Σ| ≥1. Then Σ* is:

1. empty
2. countably infinite
3. finite
4. uncountably infinite
5. none of a-d

5. Which of the following languages does the regular expression (a U b U ø* )* stand for:

1. {a}*
2. {ε}*
3. {b}*
4. {a, b}*
5. none of a-d

6. Which of the following languages does the regular expression (a U b)(a U b U ø* )* stand for:

1. {a}*
2. {ε}*
3. {b}*
4. {a, b}*
5. none of a-d

Answers:

1 c, 2 d, 3 d, 4 b, 5 d, 6 e