Tribhuvan University
Bachelor of Science in Computer Science and Information Technology
Semester 4 · TU Board 2076
Course Title: Theory of Computation (CSC262)
Full Marks: 60Pass Marks: 24Time: 3 hours
Candidates are required to give their answers in their own words as far as practicable. The figures in the margin indicate full marks.
Group A
Attempt any Two questions. (2x10=20)(2 × 10 = 20)
- 1.10
Define the NFA with ε-transition and ε-closure of a state. Show that for every regular expression r, representing a language L, there is ε-NFA accepting the same language. Also convert regular expression (a+b)ab into equivalent Finite Automata.
- 2.10
How can you define the language accepted by a PDA? Explain how a PDA accepting language by empty stack is converted into an equivalent PDA accepting by final state and vice-versa.
- 3.10
Define a Turing machine. Construct a TM that accept L = {wcw^R | w∈(0, 1) and c is ε or 0 or 1. Show that string 0110 is accepted by this TM with sequence of Instantaneous Description (ID).
Group B
Attempt any Eight questions. (8x5=40)(8 × 5 = 40)
- 4.5
Give the formal definition of DFA. Construct a DFA accepting all strings of {0, 1} with even number of 0's and even number of 1's.
- 5.5
Define Chomsky Normal Form and Greibach Normal Form in reference to CFG. Give a suitable example of each.
- 6.5
Give the regular expressions for following language over alphabet {0, 1}.
- Set of all strings with 2^nd symbol from right is 1.
- Set of all strings starting with 00 or 11 and ending with 10 or 01.
Answer comingAlso asked in 2078
- 7.5
Show that language L={0^m1^m | m>=1} is not a regular language.
Answer comingAlso asked in 2078
- 8.5
Describe the Turing machines with multiple tape, multiple track and storage in state.
- 9.5
Construct a NFA accepting language of {0, 1} with each string ending with 01 and convert it into equivalent DFA.
- 10.5
Construct a PDA accepting language over {0, 1} representing strings with equal no of 0s and1s. Show by sequence of IDs that 0101 is accepted by this PDA.
- 11.5
Define complexity of a Turing machine. Explain about big Oh, big Omega and big Theta notation used for complexity measurement.
- 12.5
What do you mean by tractable and Intractable problems? Explain with reference to TM.
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