Theory of Computation
Finite Automata and Regular Language
Marks 1Marks 2Marks 5
Push Down Automata and Context Free Language
Marks 1Marks 2
Undecidability
Marks 1Marks 2
Recursively Enumerable Language and Turing Machine
Marks 1Marks 2
1
GATE CSE 2022
MCQ (More than One Correct Answer)
+1
-0

Which of the following statements is/are TRUE?

A
Every subset of a recursively enumerable language is recursive.
B
If a language L and its complement $$\overline L $$ are both recursively enumerable, then L must be recursive.
C
Complement of a context-free language must be recursive.
D
If L1 and L2 are regular, then L1 $$\cap$$ L2 must be deterministic context-free.
2
GATE CSE 2020
MCQ (Single Correct Answer)
+1
-0.33
Consider the language
L = { $${a^n}|n \ge 0$$ } $$ \cup $$ { $${a^n}{b^n}|n \ge 0$$ }
and the following statements.

I. L is deterministic context-free.
II. L is context-free but not deterministic context-free.
III. L is not LL(k) for any k.

Which of the above statements is/are TRUE?
A
I only
B
II only
C
I and III only
D
III only
3
GATE CSE 2016 Set 2
MCQ (Single Correct Answer)
+1
-0.3
Consider the following types of languages: $${L_1}:$$ Regular, $${L_2}:$$ Context-free, $${L_3}:$$ Recursive, $${L_4}:$$ Recursively enumerable. Which of the following is/are TRUE?

$$\,\,\,\,\,\,\,{\rm I}.\,\,\,\,\,\,\,$$ $$\overline {{L_3}} \cup {L_4}$$ is recursively enumerable
$$\,\,\,\,\,{\rm I}{\rm I}.\,\,\,\,\,\,\,$$ $$\overline {{L_2}} \cup {L_3}$$ is recursive
$$\,\,\,{\rm I}{\rm I}{\rm I}.\,\,\,\,\,\,\,$$ $$L_1^ * \cap {L_2}$$ is context-free
$$\,\,\,{\rm I}V.\,\,\,\,\,\,\,$$ $${L_1} \cup \overline {{L_2}} $$ is context-free

A
$${\rm I}$$ only
B
$${\rm I}$$ and $${\rm III}$$ only
C
$${\rm I}$$ and $${\rm IV}$$ only
D
$${\rm I},$$ $${\rm II}$$ and $${\rm III}$$ only
4
GATE CSE 2015 Set 2
MCQ (Single Correct Answer)
+1
-0.3
Consider the following statements.

$$\,\,\,$$ $${\rm I}.\,\,\,\,\,\,\,\,\,$$ The complement of every Turing decidable language is Turing decidable
$$\,$$ $${\rm II}.\,\,\,\,\,\,\,\,\,$$ There exists some language which is in $$NP$$ but is not Turing decidable
$${\rm III}.\,\,\,\,\,\,\,\,\,$$ If $$L$$ is a language in $$NP,$$ $$L$$ is Turing decidable

Which of the above statements is/are true?

A
Only $${\rm I}$$$${\rm I}$$
B
Only $${\rm III}$$
C
Only $${\rm I}$$ and $${\rm II}$$
D
Only $${\rm I}$$ and $${\rm III}$$
GATE CSE Subjects
Theory of Computation
Operating Systems
Algorithms
Digital Logic
Database Management System
Data Structures
Computer Networks
Software Engineering
Compiler Design
Web Technologies
General Aptitude
Discrete Mathematics
Programming Languages
Computer Organization