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Regular expressions and finite automata, Context-free grammars and push-down automata, Regular and context-free languages, Pumping lemma, Turing machines and undecidability.

$$\scriptsize{\overset{{\large{\textbf{Mark Distribution in Previous GATE}}}}{\begin{array}{|c|c|c|c|c|c|c|c|}\hline
\textbf{Year}&\textbf{2024-1} & \textbf{2024-2} & \textbf{2023} & \textbf{2022} & \textbf{2021-1}&\textbf{2021-2}&\textbf{Minimum}&\textbf{Average}&\textbf{Maximum}
\\\hline\textbf{1 Mark Count} &1&1&3& 2 &2&3& 1&2&3
\\\hline\textbf{2 Marks Count} &2&3&3& 3 &3&4& 2&3&4
\\\hline\textbf{Total Marks} &5&7&9& 8 &8&11&\bf{5}&\bf{8}&\bf{11}\\\hline
\end{array}}}$$

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Recent questions in Theory of Computation

#4441
1.7k
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1 answers
4 votes
CFL and DCFL
If L1 = { anbncm | n.m >0 }L2 = { anbmcm | n, m > 0}Which of these following are false?1) L1 ∩ L2 is CFL.2) L1 ∪ L2 is CFL.3) L1 and L2 are CFL ... ∩ L2 is CSL.I think (1) is FALSE as L1 ∩ L2 becomes CSL.PLease correct me if iam wrong.
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#4442
2.1k
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2 answers
0 votes
Recursive enumerable sets
A is recursive if both A and its complement are accepted by turing machineTrue or false
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#4443
444
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2 answers
0 votes
finite language, cfl
Is {a^nb^n|n>0} a finite language?
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#4444
431
views
0 answers
0 votes
http://www.cs.rice.edu/~nakhleh/COMP481/
Can anybody please explain this reduction and rice theorem.http://www.cs.rice.edu/~nakhleh/COMP481/Thanks
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#4445
510
views
2 answers
0 votes
closure property of cfl
Can complement of a non-regular language be regular?
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#4446
554
views
1 answers
0 votes
Digital Electronics
Size of rom for converting binary code to gray code?
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#4447
1.3k
views
2 answers
0 votes
regular expression
write the regular expression for the given language L= { W | NO OF a mod 2= 1} (odd no of a's )
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#4448
531
views
1 answers
0 votes
Doubt
can language wcwR accepted by a single queue?i want someone to parseabcRcba using a QUEUE
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#4449
595
views
3 answers
0 votes
Regular Expression
Given statement is true or false 1. L is regular language $\Leftrightarrow$ Ǝ a regular expression without $\bigstar$ answer in detail
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#4450
2.8k
views
3 answers
2 votes
Theory proof
1. The complement of a finite language is always infinite2. The complement of an infinite language may be finite or infinite ..both statements are true .. i can proof using examples .. can someone give me logical theory proof ?
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#4451
423
views
1 answers
0 votes
Test by Bikram | Mock GATE | Test 4 | Question: 53
Which of the following languages over the alphabet set $\{ a, b \}$ is described by the regular expression$a^\ast b$(aa)$^\ast b$ ?The set of all strings ... of all strings ending with $ b'$.The set of all strings having sub sequence $bb$.
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#4452
233
views
1 answers
1 votes
Test by Bikram | Mock GATE | Test 4 | Question: 44
Which of the following regular expressions describes the same set of strings as $\left ( a^*+b \right )^*$ $\left ( c+d \right )$ ... $a^{\ast }\left ( c+d \right )+ b^{\ast }\left ( c+d \right )$
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#4453
524
views
0 answers
2 votes
Test by Bikram | Mock GATE | Test 4 | Question: 35
Let $DM$ be a single-tape, Deterministic Turing machine with tape alphabet $\left \{ blank,0,1 \right \}$, and let $C_i$ denote the (possibly infinite) ... during the computation $C_i.$III onlyI and III onlyII and III onlyI, II, and III
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#4454
755
views
1 answers
4 votes
Test by Bikram | Mock GATE | Test 4 | Question: 26
Consider the languages $A$ and $B$, each over the alphabet set $\left \{ a,b \right \}$.Here, $B=\{ w \mid w$ contains some $x \in A$ as a sub-string $\}.$ ... $B$ is context-free. II only II and III I and III only I, II and III
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#4455
492
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2 answers
0 votes
Test by Bikram | Mock GATE | Test 4 | Question: 23
The definition of a language $N$ with alphabet set $\left \{ x \right \}$ ... }$ to recognize $N$ is _________.$p+m$p+1$m+1$2^\left ( p+1 \right )$
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#4456
424
views
1 answers
2 votes
Test by Bikram | Mock GATE | Test 4 | Question: 9
If $L$ is the set of all strings over $\{ x,y\}$ containing at least one $x$, then which of the following regular expressions does not generate $L$?$(x+y)^* x(y+y)^*$y^*x ( x+y)^*$( x+y)^* x$( x+y)^* xy^*$
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#4457
998
views
1 answers
0 votes
Peter Linz Exercise 11.1
If L is recursive, is it necessarily true that L+ is also recursive?
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#4458
270
views
0 answers
0 votes
Peter Linz Exercise 11.1
Prove that the complement of context free language is recursive.
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#4459
466
views
2 answers
1 votes
Toc question
Consider the two given languages :A={x:x is an integer and divisible by 2) B ={2x:x is an integer }.Which of the following is correct?A) A is accepted ... not by AC) Both A and B are accepted by an automataD)None are accepted by automata
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#4460
1.2k
views
3 answers
0 votes
TOC QUESTION
Which of the following is not true?A)Class of All languages is not countableB)Every language in P is also in NPC)Every language in NP is decidabale.D)There are some languages in NP but not in P
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