Question 1

Basic limitation of FSM is that it

Accepted Answer

A) Cannot remember arbitrary large amount of information 
B) Sometimes fails to recognize grammars that are regular 
C) Sometimes recognizes grammars are not regular 
D) None of these 
A) Cannot remember arbitrary large amount of information 
B) Sometimes fails to recognize grammars that are regular 
C) Sometimes recognizes grammars are not regular 
D) None of these A

Question 2

Consider a language L for which there exists a Turing machine , T, that accepts every word in L and either rejects or loops for every word that is not in L. The language L is

Accepted Answer

A) NP hard 
B) NP complete 
C) Recursive 
D) Recursively enumerable 
A) NP hard 
B) NP complete 
C) Recursive 
D) Recursively enumerable D

Question 3

The concept of FSA is much used in this part of the compiler

Accepted Answer

A) Lexical analysis 
B) Parser 
C) Code generation 
D) Code optimization 
A) Lexical analysis 
B) Parser 
C) Code generation 
D) Code optimization A

Question 4

The Family of recursive language is not closed under which of the following operations:

Accepted Answer

A) Union 
B) Intersection 
C) Complementation 
D) None of the above. 
A) Union 
B) Intersection 
C) Complementation 
D) None of the above.

Question 5

Recursive languages are

Accepted Answer

A) A proper superset of CFL 
B) Always recognized by PDA 
C) Are also called type 0 languages 
D) Always recognized by FSA 
A) A proper superset of CFL 
B) Always recognized by PDA 
C) Are also called type 0 languages 
D) Always recognized by FSA

Question 6

The logic of pumping lemma is a good example of

Accepted Answer

A) Pigeon-hole principle 
B) Divide-and-conquer technique 
C) Recursion 
D) Iteration 
A) Pigeon-hole principle 
B) Divide-and-conquer technique 
C) Recursion 
D) Iteration

Question 7

Let L be a language defined over an alphabet ?,then the language of strings , defined over ?, not belonging to L denoted by LC or L. is called :

Accepted Answer

A) Non regular language of L 
B) Complement of the language L 
C) None of the given 
D) All of above 
A) Non regular language of L 
B) Complement of the language L 
C) None of the given 
D) All of above

Question 8

Which of the following statements is wrong?

Accepted Answer

A) The regular sets are closed under intersection 
B) The class of regular sets is closed under substitution 
C) The class of regular sets is closed under homomorphism 
D) Context Sensitive Grammar(CSG) can be recognized by Finite State Machine 
A) The regular sets are closed under intersection 
B) The class of regular sets is closed under substitution 
C) The class of regular sets is closed under homomorphism 
D) Context Sensitive Grammar(CSG) can be recognized by Finite State Machine

Question 9

Fred created a new automaton model which is a push down automaton but with two stacks and the added ability of having commands which do not read input tape but which can pop from one stack and push into the other.This new automaton can recognize (choose strongest result)

Accepted Answer

A) Context Free Language 
B) Context sensitive language 
C) Regular language 
D) Languages recognizable by Turing machine 
A) Context Free Language 
B) Context sensitive language 
C) Regular language 
D) Languages recognizable by Turing machine

Question 10

If a language is denoted by a regular expression L = ( x )* (x y x ), then which of the following is not a legal string within L ?

Accepted Answer

A) yx 
B) xyx 
C) x 
D) xyxyx 
A) yx 
B) xyx 
C) x 
D) xyxyx

Question 11

Grammar that produce more than one Parse tree for same sentence is:

Accepted Answer

A) Ambiguous 
B) Unambiguous 
C) Complementation 
D) Concatenation 
A) Ambiguous 
B) Unambiguous 
C) Complementation 
D) Concatenation

Question 12

Consider the following problem x. Given a Turing machine M over the input alphabet ?, any state q of M. And a word w ? ?*, does the computation of M on w visit the state q? Which of the following statements about x is correct?

Accepted Answer

A) X is decidable 
B) X is undecidable but partially decidable 
C) X is undecidable and not even partially decidable 
D) X is not a decision problem 
A) X is decidable 
B) X is undecidable but partially decidable 
C) X is undecidable and not even partially decidable 
D) X is not a decision problem

Question 13

Which of the following problems is undecidable?

Accepted Answer

A) Membership problem for CFGs 
B) Ambiguity problem for CFGs. 
C) Finiteness problem for FSAs. 
D) Equivalence problem for FSAs. 
A) Membership problem for CFGs 
B) Ambiguity problem for CFGs. 
C) Finiteness problem for FSAs. 
D) Equivalence problem for FSAs.

Question 14

Let L denotes the language generated by the grammar S - OSO/00. Which of the following is true?

Accepted Answer

A) L = O 
B) L is regular but not O 
C) L is context free but not regular 
D) L is not context free 
A) L = O 
B) L is regular but not O 
C) L is context free but not regular 
D) L is not context free

Question 15

The following grammar G = (N, T, P, S)**spaceN = {S, A, B, C, D, E}**spaceT = {a, b, c}**spaceP : S ? aAB**spaceAB ? CD**spaceCD ? CE**spaceC ? aC**spaceC ? b**spacebE ? bc is

Accepted Answer

A) is type 3 
B) is type 2 but not type 3 
C) is type 1 but not type 2 
D) is type 0 but not type 1 
A) is type 3 
B) is type 2 but not type 3 
C) is type 1 but not type 2 
D) is type 0 but not type 1

Question 16

Consider a string s over (0+1)*. The number of 0's in s is denoted by no(s) and the number of 1's in s is denoted by n1(s). The language that is not regular is

Accepted Answer

A) L = {s ? (0+1)* I for every prefix s' of s, I no(s')-n1(s') I ? 2} 
B) L = {s ? (0+1)* I no(s) mod 7 = n1(s) mod 5 = 0} 
C) L = {s ? (0+1)* I no(s) is a 3 digit prime} 
D) L = {s ? (0+1)* I no(s)-n1(s) I ? 4 
A) L = {s ? (0+1)* I for every prefix s' of s, I no(s')-n1(s') I ? 2} 
B) L = {s ? (0+1)* I no(s) mod 7 = n1(s) mod 5 = 0} 
C) L = {s ? (0+1)* I no(s) is a 3 digit prime} 
D) L = {s ? (0+1)* I no(s)-n1(s) I ? 4

Question 17

If L1 and L2 are context free language and R a regular set, then which one of the languages below is not necessarily a context free language?

Accepted Answer

A)  L1 L2 
B)  L1 ? L2 
C)  L1 ? R 
D)  L1 ? L2 
A)  L1 L2 
B)  L1 ? L2 
C)  L1 ? R 
D)  L1 ? L2

Question 18

Which of the following pairs have DIFFERENT expressive power?

Accepted Answer

A) Deterministic finite automata (DF
A)  and Non-Deterministic finite automata(NF
A)  
B) Deterministic push down automata (DPD
A)  and Non-deterministic pushdown automata 
C) Deterministic single-tape Turing machine and Non-deterministic single-tape Turing Machine 
D) Single-tape Turing machine and multi-tape Turing machine 
A) Deterministic finite automata (DF
A)  and Non-Deterministic finite automata(NF
A)  
B) Deterministic push down automata (DPD
A)  and Non-deterministic pushdown automata 
C) Deterministic single-tape Turing machine and Non-deterministic single-tape Turing Machine 
D) Single-tape Turing machine and multi-tape Turing machine

Question 19

Any Language generated by an unrestricted grammar is:

Accepted Answer

A) Recursive 
B) Recursively Enumerable 
C) Not Recursive 
D) None of the above 
A) Recursive 
B) Recursively Enumerable 
C) Not Recursive 
D) None of the above

Question 20

Context free grammar is not closed under

Accepted Answer

A) Product operation 
B) Union 
C) Complementation 
D) kleene star 
A) Product operation 
B) Union 
C) Complementation 
D) kleene star

Basic limitation of FSM is that it

Consider a language L for which there exists a Turing machine , T, that accepts every word in L and either rejects or loops for every word that is not in L. The language L is

The concept of FSA is much used in this part of the compiler

The Family of recursive language is not closed under which of the following operations:

Recursive languages are

The logic of pumping lemma is a good example of

Let L be a language defined over an alphabet ?,then the language of strings , defined over ?, not belonging to L denoted by LC or L. is called :

Which of the following statements is wrong?

Fred created a new automaton model which is a push down automaton but with two stacks and the added ability of having commands which do not read input tape but which can pop from one stack and push into the other.This new automaton can recognize (choose strongest result)

If a language is denoted by a regular expression L = ( x )* (x y x ), then which of the following is not a legal string within L ?

Grammar that produce more than one Parse tree for same sentence is:

Consider the following problem x. Given a Turing machine M over the input alphabet ?, any state q of M. And a word w ? ?*, does the computation of M on w visit the state q? Which of the following statements about x is correct?

Which of the following problems is undecidable?

Let L denotes the language generated by the grammar S - OSO/00. Which of the following is true?

The following grammar G = (N, T, P, S)spaceN = {S, A, B, C, D, E}spaceT = {a, b, c}spaceP : S ? aABspaceAB ? CDspaceCD ? CEspaceC ? aCspaceC ? bspacebE ? bc is

Consider a string s over (0+1)*. The number of 0's in s is denoted by no(s) and the number of 1's in s is denoted by n1(s). The language that is not regular is

If L₁ and L₂ are context free language and R a regular set, then which one of the languages below is not necessarily a context free language?

Which of the following pairs have DIFFERENT expressive power?

Any Language generated by an unrestricted grammar is:

Context free grammar is not closed under

Formal Languages and Automata Theory: Part A

Computational Theory : Grammar, Language, and Complexity

Omputer Science and Theory of Computation

Automata and Turing Machines

Filters

Exam 2: Formal Languages and Automata Theory: Part B

Basic limitation of FSM is that it

Consider a language L for which there exists a Turing machine , T, that accepts every word in L and either rejects or loops for every word that is not in L. The language L is

The concept of FSA is much used in this part of the compiler

The Family of recursive language is not closed under which of the following operations:

Recursive languages are

The logic of pumping lemma is a good example of

Let L be a language defined over an alphabet ?,then the language of strings , defined over ?, not belonging to L denoted by LC or L. is called :

Which of the following statements is wrong?

Fred created a new automaton model which is a push down automaton but with two stacks and the added ability of having commands which do not read input tape but which can pop from one stack and push into the other.This new automaton can recognize (choose strongest result)

If a language is denoted by a regular expression L = ( x )* (x y x ), then which of the following is not a legal string within L ?

Grammar that produce more than one Parse tree for same sentence is:

Consider the following problem x. Given a Turing machine M over the input alphabet ?, any state q of M. And a word w ? ?*, does the computation of M on w visit the state q? Which of the following statements about x is correct?

Which of the following problems is undecidable?

Let L denotes the language generated by the grammar S - OSO/00. Which of the following is true?

The following grammar G = (N, T, P, S)**spaceN = {S, A, B, C, D, E}**spaceT = {a, b, c}**spaceP : S ? aAB**spaceAB ? CD**spaceCD ? CE**spaceC ? aC**spaceC ? b**spacebE ? bc is

Consider a string s over (0+1)*. The number of 0's in s is denoted by no(s) and the number of 1's in s is denoted by n1(s). The language that is not regular is

If L1 and L2 are context free language and R a regular set, then which one of the languages below is not necessarily a context free language?

Which of the following pairs have DIFFERENT expressive power?

Any Language generated by an unrestricted grammar is:

Context free grammar is not closed under

Formal Languages and Automata Theory: Part A

Computational Theory : Grammar, Language, and Complexity

Omputer Science and Theory of Computation

Automata and Turing Machines

Filters

The following grammar G = (N, T, P, S)spaceN = {S, A, B, C, D, E}spaceT = {a, b, c}spaceP : S ? aABspaceAB ? CDspaceCD ? CEspaceC ? aCspaceC ? bspacebE ? bc is

If L₁ and L₂ are context free language and R a regular set, then which one of the languages below is not necessarily a context free language?