Automata Theory Multiple Choice Questions on “Epsilon Closures”.
1. Which of the following does not belong to input alphabet if S={a, b}* for any language?
a) a
b) b
c) e
d) none of the mentioned
Answer: c
Clarification: The automaton may be allowed to change its state without reading the input symbol using epsilon but this does not mean that epsilon has become an input symbol. On the contrary, one assumes that the symbol epsilon does not belong to any alphabet.
2. The number of final states we need as per the given language?
Language L: {an| n is even or divisible by 3}
a) 1
b) 2
c) 3
d) 4
Answer: b
3. State true or false:
Statement: Both NFA and e-NFA recognize exactly the same languages.
a) true
b) false
Answer: a
Clarification: e-NFA do come up with a convenient feature but nothing new.They do not extend the class of languages that can be represented.
4. Design a NFA for the language:
L: {an| n is even or divisible by 3}
Which of the following methods can be used to simulate the same.
a) e-NFA
b) Power Construction Method
c) Both (a) and (b)
d) None of the mentioned
Answer: c
Clarification: It is more convenient to simulate a machine using e-NFA else the method of Power Construction is used from the union-closure of DFA’s.