Computer Science and Information Technology
GATE CSE Theory of Computation PYQs
Build your understanding with focused practice from past exam papers.
Questions 11–20 of 83. Imported answers require independent review unless marked reviewed.
Question 25
Open questionCSMCQ1 markNeeds review
Let
be Context Free Grammars (CFGs) and
be a regular expression. For a grammar
, let
denote the language generated by
.Which ONE among the following questions is decidable?
Your answerChoose one option.
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Open questionCSMSQ1 markNeeds review
A regular language
is accepted by a non-deterministic finite automaton (NFA) with
states. Which of the following statement(s) is/are FALSE?Your answerSelect all correct options. You can choose more than one.
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Open questionCSMSQ1 markNeeds review
Consider the two lists List I and List II given below:
List I | List II |
|---|---|
(i) Context free languages | (a) Closed under union |
(ii) Recursive languages | (b) Not closed under complementation |
(iii) Regular languages | (c) Closed under intersection |
For matching of items in List I with those in List II, which of the following option(s) is/are CORRECT?
Your answerSelect all correct options. You can choose more than one.
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 44
Open questionCSMCQ2 marksNeeds review
Consider the following two languages over the alphabet
:
Which ONE of the following statements is CORRECT?
Your answerChoose one option.
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Open questionCSMCQ2 marksNeeds review
Consider the following two languages over the alphabet
, where
and
are natural numbers.
Which ONE of the following statements is CORRECT?
Your answerChoose one option.
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Open questionCSMSQ2 marksNeeds review
Consider the following deterministic finite automaton (DFA) defined over the alphabet,
. Identify which of the following language(s) is/are accepted by the given DFA. 
Your answerSelect all correct options. You can choose more than one.
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Open questionCSMSQ2 marksNeeds review
Consider two grammars
and
with the production rules given below:
where
,
,
,
,
,
are the terminals.Which of the following option(s) is/are CORRECT?
Your answerSelect all correct options. You can choose more than one.
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Open questionCSMSQ2 marksNeeds review
Let
. For
, and
, let
denote the number of occurrences of
in
.Which one or more of the following option(s) define(s) regular language(s)?
Your answerSelect all correct options. You can choose more than one.
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Open questionCSNAT2 marksNeeds review
Let
. For
, let
be the product of symbols in
modulo 7. We take
, where
is the null string.For example,
.Define
.The number of states in a minimum state DFA for
is __________. (Answer in integer)Log in to check the answer
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Open questionCSMCQ1 markNeeds review
Which one of the following regular expressions is equivalent to the language accepted by the DFA given below?

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