Given the language L-{ab, aa, baa}, which of the following strings are in L*?
1) abaabaaabaa
2) aaaabaaaa
3) baaaaabaaaab
4) baaaaabaa

1,2 and 3
2,3 and 4
1,2 and 4
1,3 and 4
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Push down machine represents

Type 0 Grammar
Type 1 grammar
Type-2 grammar
Type-3 grammar
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The behavior of a NFA can be stimulated by DFA 

always
sometimes
never
depend on NFA
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Both statements S1 and S2 are incorrect.
S1 is incorrect and S2 is correct.
S1 is correct and S2 is incorrect.
Both statements S1 and S2 are correct.
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A
B
C
D
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Which of the following is not primitive recursive but partially recursive? 

Carnot function
Rieman function
Bounded function
Ackermann function
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Consider the following grammar.
S ::= AB
A ::= a
A ::= BaB
B ::= bbA
Which of the following is false?


No string produced by the grammar has four consecutive b s
No string produced by the grammar has three consecutive a s
No string produced by the grammar has an odd number of consecutive b s
The length of every string produced by the grammar is even.
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Set of regular languages over a given alphabet set,is not closed under 

Union
Complementation
Intersection
None of the above
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Consider the regular expression (a + b) (a + b) … (a + b) (n-times). The minimum number of states in finite automaton that recognizes the language represented by this regular expression contains

n states
n + 1 states
n + 2 states
2n states
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LL grammar for the language L = {an bm cn+m | m=0, n=0} is


A
B
C
D
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The logic of pumping lemma is a good example of 

The pigeon hole principle
Divide and conquer method
Iteration
Recursion
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If every string of a language can be determined whether it is legal or illegal in finite time the language is called 

Decidable
Undecidable
Interpretive
Non deterministic
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Context free language can be recognized by 

Finite State Automaton
Linear bounded automaton
Pushdown automaton
Both B and C
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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)

Context free language
Context sensitive language
Regular language
Languages recognizable by Turing machine
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Given the following productions of a grammar :


The language corresponding to the given grammar is a set of even number of a s.
The language corresponding to the given grammar is a set of odd number of a s.
The language corresponding to the given grammar is a set of even number of a’s followed by odd number of b s.
The language corresponding to the given grammar is a set of odd number of a’s followed by even number of b s.
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Consider the set of strings on {0,1} in which, every substring of 3 symbols has at most two zeros. For example, 001110 and 011001 are in the language, but 100010 is not. All strings of length less than 3 are also in the language. A partially completed DFA that accepts this language is shown below.


A
B
C
D
      _____________________________________________________________________________________


A
B
C
D
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The regular expression for the following DFA


ab*(b + aa*b)*
a*b(b + aa*b)*
a*b(b* + aa*b)
a*b(b * + aa*b)*
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FSM can recognize 

Any grammar
Only CFG
Any unambiguous grammar
Only regular grammar
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Assume statements S1 and S2 defined as :
S1 : L2-L1 is recursive enumerable where L1 and L2 are recursive and recursive enumerable respectively.
S2 : The set of all Turing machines is countable. 
Which of the following is true ?


S1 is correct and S2 is not correct.
Both S1 and S2 are correct.
Both S1 and S2 are not correct.
S1 is not correct and S2 is correct.
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Which of the following is the most general phase structured grammar ?

Regular
Context-sensitive
Context free
None of the above
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A FSM can be used to add how many given integers? 

1
3
4
5
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The language accepted by the nondeterministic pushdown automaton


L(abb*a)
{a} U L(abb*a)
L(ab*a)
{a} U L(ab*a)
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Consider the following statements :
I. Recursive languages are closed under complementation.
II. Recursively enumerable languages are closed under union.
III. Recursively enumerable languages are closed under complementation.
Which of the above statements are true ?


I only
I and II
I and III
I and III
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6 Files F1,F2,F3,F4,F5 and F6 have 100,200,50,80,120,150 records repectively.
In what order should they be sorted so as to optimize activity? Assume each file is accessed with the same frequency.

F3,F4,F1,F5,F6,F2
F2,F6,F5,F1,F4,F3
F1,F2,F3,F4,F5,F6
Ordering is immaterial as all files are accessed with the same frequency
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Following grammar
S-> bS
S -> b
S -> aA
A -> bA


Type -3 grammar
Type -2 grammar
Type -1 grammar
Type -0 grammar
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Which of the following problems are decidable?
1) Does a given program ever produce an output?
2) If L is context-free language, then, is ~L also context-free?
3) If L is regular language, then, is ~L also regular?
4) If L is recursive language, then, is ~L also recursive?


1,2,3,4
1,2
2,3,4
3,4
      _____________________________________________________________________________________
The language L={abk|k>=1} is

Type -3 Grammar
Type -2 Grammar
Type -1 Grammar
Type -0 Grammar
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All strings having equal number of a and b can be recognized by 

DFA
NDFA
PDA
All of these
      _____________________________________________________________________________________
The basic limitation of a FSM is that 

It cannot remember arbitrary large amount of information
It sometimes recognizes grammar that are not regular
It sometimes fails to recognize grammars that are regular
All of the above
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How many states can a process be in ?

2
3
4
5
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Which one of the following statement is false ?

Context-free languages are closed under union
Context-free languages are closed under concatenation
Context-free languages are closed under intersection
Context-free languages are closed under Kleene closure
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Given the language L = {ab, aa, baa}, which of the following strings are in L*?
1) abaabaaabaa
2) aaaabaaaa
3) baaaaabaaaab
4) baaaaabaa


1, 2 and 3
2, 3 and 4
1, 2 and 4
1, 3 and 4
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Which is not the correct statement(s) ?
(i) Every context sensitive language is recursive.
(ii) There is a recursive language that is not context sensitive.


(i) is true, (ii) is false.
(i) is true and (ii) is true.
(i) is false, (ii) is false.
(i) is false and (ii) is true.
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A formal grammar is a___________for rewriting strings. 

Set of rules
Set of functions
Both A and B
None of the above
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Finite automata are used for pattern matching in text editors for 

Compiler lexical analysis
Programming in localized application
Both A and B
None of the above
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Two finite states are equivalent if they 

Have same number of states
Have same number of edges
Have same number of states and edges
Recognize same set of tokens
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A PDM behaves like a TM when the number of auxiliary memory it has is 

Zero
One or more
Two or more
None of these
      _____________________________________________________________________________________
Which of the following permanent database that has an entry for each terminal symbol ?

Literal table
Identifier table
Terminal table
Source table
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The language accepted by finite automata is 

Context free
Regular
Non regular
None of these
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The following CFG
S®aB|bA, A®a|as|bAA, B®b|bs|aBB
generates strings of terminals that have


Odd number of a’s and odd number of b’s
Even number of a’s and even number of b’s
Equal number of a’s and b’s
Not equal number of a’s and b’s
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An FSM can be used to add two given integers.This remark is 

True
False
May be true
None of the above
      _____________________________________________________________________________________
Context free languages are not closed under 

Union
Concatenation
Closure
Iteration
      _____________________________________________________________________________________

Given a Non-deterministic Finite Automation (NFA) with states p and r as initial and final states respectively and transition table as given below :
The minimum number of states required in Deterministic Finite Automation (DFA) equivalent to NFA is


5
4
3
2
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Which of the following is most powerful? 

DFA
NDFA
2PDA
DPDA
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Which of the following statements is/are FALSE?
(1) For every non-deterministic Turing machine, there exists an equivalent deterministic Turing machine.
(2) Turing recognizable languages are closed under union and complementation.
(3) Turing decidable languages are closed under intersection and complementation
(4) Turing recognizable languages are closed under union and intersection.


1 and 4 only
1 and 3 only
2 only
3 only
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G1 is ambiguous and G2 is not ambiguous.
G1 is ambiguous and G2 is ambiguous.
G1 is not ambiguous and G2 is ambiguous.
G1 is not ambiguous and G2 is not ambiguous.
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Finite state machine___________recognize palindromes. 

Can
Cannot
May
May not
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Given L1=L(a*baa*) and L2=L(ab*). The regular expression corresponding to language L3 = L1/L2 (right quotient) is given by

a*b
a*baa*
a*ba*
None of the above
      _____________________________________________________________________________________
If two finite state machines are equivalent they should have the same number of 

States
Edges
States and edges
None of these
      _____________________________________________________________________________________
 
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