2022 question paper
FORMAL LANGUAGE & AUTOMATA THEORY
29 questions
Q1a. The minimum number of states required to recognize an octal number divisible by 3 is: (i) 1 (ii) 3 (iii) 5 (iv) 720222m
Module 1: Introduction & Regular Languages
View this question on its own page →The minimum number of states required to recognize an octal number divisible by 3 is:
(i) 1
(ii) 3
(iii) 5
(iv) 7Q1b. For a given Moore machine, given input = 101010, the output would be of length: (i) |Input| + 1 (ii) |Input| (iii) |Input| − 1 (iv) Cannot be predicted20222m
Module 1: Introduction & Regular Languages
View this question on its own page →For a given Moore machine, given input =
101010, the output would be of length:(i) |Input| + 1
(ii) |Input|
(iii) |Input| − 1
(iv) Cannot be predictedQ1c. The total number of states and transitions required to form a Moore machine that produces residue mod 3 are: (i) 3 and 6 (ii) 3 and 5 (iii) 2 and 4 (iv) 2 and 520222m
Module 1: Introduction & Regular Languages
View this question on its own page →The total number of states and transitions required to form a Moore machine that produces residue mod 3 are:
(i) 3 and 6
(ii) 3 and 5
(iii) 2 and 4
(iv) 2 and 5Q1d. Which of the following is a correct statement? (i) Moore machine has no accepting states. (ii) Mealy machine has accepting states. (iii) We can convert Mealy to Moore but not vice versa. (iv) All of the above20222m
Module 1: Introduction & Regular Languages
View this question on its own page →Which of the following is a correct statement?
(i) Moore machine has no accepting states.
(ii) Mealy machine has accepting states.
(iii) We can convert Mealy to Moore but not vice versa.
(iv) All of the aboveQ1e. The minimum number of transitions to reach the final state as per the regular expression: \{a, b\}^* baaa is: (i) 4 (ii) 5 (iii) 6 (iv) 320222m
Module 1: Introduction & Regular Languages
View this question on its own page →The minimum number of transitions to reach the final state as per the regular expression:
is:
(i) 4
(ii) 5
(iii) 6
(iv) 3Q1f. Let w = xyz, y is the middle portion and |y| > 0. Repeating y zero or more times before checking membership in L is known as: (i) Generating (ii) Pumping (iii) Producing (iv) None of the above20222m
Module 1: Introduction & Regular Languages
View this question on its own page →Let , is the middle portion and . Repeating zero or more times before checking membership in is known as:
(i) Generating
(ii) Pumping
(iii) Producing
(iv) None of the aboveQ1g. A Turing machine that is able to simulate other Turing machines is called: (i) nested Turing machine (ii) universal Turing machine (iii) counter machine (iv) None of the above20222m
Module 4: Turing Machines (TM)
View this question on its own page →A Turing machine that is able to simulate other Turing machines is called:
(i) nested Turing machine
(ii) universal Turing machine
(iii) counter machine
(iv) None of the aboveQ1h. A recursively enumerable language L is recursive if: (i) L' is recursively enumerable (ii) every sequence of moves of T halts (iii) Both (i) and (ii) (iv) None of the above20222m
Module 5: Undecidability
View this question on its own page →A recursively enumerable language is recursive if:
(i) is recursively enumerable
(ii) every sequence of moves of halts
(iii) Both (i) and (ii)
(iv) None of the aboveQ1i. RASP stands for: (i) Random Access Storage Program (ii) Random Access Stored Program (iii) Randomly Accessed Stored Program (iv) Random Access Storage Programming20222m
Module 4: Turing Machines (TM)
View this question on its own page →RASP stands for:
(i) Random Access Storage Program
(ii) Random Access Stored Program
(iii) Randomly Accessed Stored Program
(iv) Random Access Storage ProgrammingQ1j. A language L is Turing decidable if: (i) recursive (ii) TM recognizes L (iii) TM accepts L (iv) None of the above20222m
Module 4: Turing Machines (TM)
View this question on its own page →A language is Turing decidable if:
(i) recursive
(ii) TM recognizes
(iii) TM accepts
(iv) None of the aboveQ2a. Design a DFA for strings over \{a, b\} containing at least three occurrences of bbb (overlapping allowed). Example: bbbbbb is accepted.20227m
Module 1: Introduction & Regular Languages
View this question on its own page →Design a DFA for strings over containing at least three occurrences of
bbb(overlapping allowed). Example:bbbbbbis accepted.Q2b. Let L \subseteq \{0,1,2\}^* be strings without consecutive identical symbols (no 00, no 11, no 22). Design a DFA for L.20227m
Module 1: Introduction & Regular Languages
View this question on its own page →Let be strings without consecutive identical symbols (no , no , no ). Design a DFA for .
Q3a. Prove that if L is accepted by a PDA, then L can be generated by a CFG.20227m
Module 2: Context-Free Languages (CFL) and PDA
View this question on its own page →Prove that if is accepted by a PDA, then can be generated by a CFG.
Q3b. Design an NPDA (empty stack and final state acceptance) for: L = \{\text{palindromes over } \{a,b\}\}20227m
Module 2: Context-Free Languages (CFL) and PDA
View this question on its own page →Design an NPDA (empty stack and final state acceptance) for:
Q4a. Design Mealy and Moore machines to detect the sequence 1010 (overlapping allowed). Then convert the Moore machine into a Mealy machine and prove equivalence.20227m
Module 1: Introduction & Regular Languages
View this question on its own page →Design Mealy and Moore machines to detect the sequence
1010(overlapping allowed). Then convert the Moore machine into a Mealy machine and prove equivalence.Q4b. Show whether the given grammar is ambiguous: S \to a \mid abSb \mid aAb \\ A \to bS \mid aAAb20227m
Module 2: Context-Free Languages (CFL) and PDA
View this question on its own page →Show whether the given grammar is ambiguous:
Q5a. Give examples of L_1 and L_2 such that: (i) L_1 is regular, L_2 is not regular, and L_1 - L_2 is regular. (ii) L_1 and L_2 are not regular but L_1 \cup L_2 is regular.20227m
Module 1: Introduction & Regular Languages
View this question on its own page →Give examples of and such that:
(i) is regular, is not regular, and is regular.
(ii) and are not regular but is regular.Q5b. Show that the language of palindromes over \{a, b\} is not regular.20227m
Module 1: Introduction & Regular Languages
View this question on its own page →Show that the language of palindromes over is not regular.
Q6a. Construct a CFG for: \{ 0^i 1^j 2^k \mid i + j \ge 2k \}20227m
Module 2: Context-Free Languages (CFL) and PDA
View this question on its own page →Construct a CFG for:
Q6b. Convert the CFG to GNF: S \to AB \mid BC \\ A \to aB \mid bA \mid a \\ B \to bB \mid cC \mid b \\ C \to c20227m
Module 2: Context-Free Languages (CFL) and PDA
View this question on its own page →Convert the CFG to GNF:
Q7a. Design a Turing machine that accepts all palindromes over: \Sigma = \{ a, b \}20227m
Module 4: Turing Machines (TM)
View this question on its own page →Design a Turing machine that accepts all palindromes over:
Q7b. Explain the Myhill–Nerode theorem for minimization of automata with an example.20227m
Module 1: Introduction & Regular Languages
View this question on its own page →Explain the Myhill–Nerode theorem for minimization of automata with an example.
Q8a. Construct FOLLOW sets for the grammar: E \to T E' \\ E' \to +\,T\,E' \mid \varepsilon \\ T \to F T' \\ T' \to -\,F\,T' \mid \varepsilon \\ F \to (E) \mid id20227m
Module 2: Context-Free Languages (CFL) and PDA
View this question on its own page →Construct FOLLOW sets for the grammar:
Q8b. Show that the language: L = \{ a^{n^2} b^n \mid n \ge 0 \} is not regular.20227m
Module 1: Introduction & Regular Languages
View this question on its own page →Show that the language:
is not regular.
Q9a. Prove that the halting problem for Turing machines is recursively undecidable.20227m
Module 5: Undecidability
View this question on its own page →Prove that the halting problem for Turing machines is recursively undecidable.
Q9b(i). Write a short note on Deterministic PDA vs. Non-deterministic PDA.20227m
Module 2: Context-Free Languages (CFL) and PDA
View this question on its own page →Write a short note on Deterministic PDA vs. Non-deterministic PDA.
Q9b(ii). Write a short note on Chomsky Normal Form (CNF).20227m
Module 2: Context-Free Languages (CFL) and PDA
View this question on its own page →Write a short note on Chomsky Normal Form (CNF).
Q9b(iii). Write a short note on Multi-stack Turing Machine.20227m
Module 4: Turing Machines (TM)
View this question on its own page →Write a short note on Multi-stack Turing Machine.
Q9b(iv). Write a short note on Finite-state Machine (FSM).20227m
Module 1: Introduction & Regular Languages
View this question on its own page →Write a short note on Finite-state Machine (FSM).