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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.

$$\scriptsize{\overset{{\large{\textbf{Mark Distribution in Previous GATE}}}}{\begin{array}{|c|c|c|c|c|c|c|c|}\hline
\textbf{Year}& \textbf{2022} & \textbf{2021-1}&\textbf{2021-2}&\textbf{2020}&\textbf{2019}&\textbf{2018}&\textbf{2017-1}&\textbf{2017-2}&\textbf{2016-1}&\textbf{2016-2}&\textbf{Minimum}&\textbf{Average}&\textbf{Maximum}
\\\hline\textbf{1 Mark Count} & 2 &2&3&3&2&2&2&3&3&3&2&2.5&3
\\\hline\textbf{2 Marks Count} & 3 &3&4&3&3&3&5&3&3&3&3&3.3&5
\\\hline\textbf{Total Marks} & 8 &8&11&9&8&8&12&9&9&9&\bf{8}&\bf{9.1}&\bf{12}\\\hline
\end{array}}}$$

Highest voted questions in Theory of Computation

44 votes
7 answers
81
Consider a CFG with the following productions.$S \to AA \mid B$$A \to 0A \mid A0 \mid 1$$B \to 0B00 \mid 1$$S$ is the start symbol, $A$ and $B$ are non-terminals and 0 an...
43 votes
6 answers
86
Consider the following Finite State Automaton:The language accepted by this automaton is given by the regular expression$b^*ab^*ab^*ab^*$$(a + b)^*$$b^*a(a+b)^*$$b^*ab^*a...
43 votes
4 answers
87
If $G$ is a context free grammar and $w$ is a string of length $l$ in $L(G)$, how long is a derivation of $w$ in $G$, if $G$ is in Chomsky normal form?$2l$$2l +1$$2l -1$$...
42 votes
7 answers
88
Consider the regular expression $R = (a + b)^* (aa + bb) (a + b)^*$Which deterministic finite automaton accepts the language represented by the regular expression $R$?
42 votes
6 answers
89
Given the following state table of an FSM with two states $A$ and $B$,one input and one output.$$\small\begin{array}{|c|c|c|c|c|c|}\hline \textbf{PRESENT} & \textbf{PRESE...
42 votes
8 answers
90
Which of the following regular expression identities is/are TRUE?$r^{(^\ast)} =r^\ast$$(r^\ast s^\ast)=(r+s)^\ast$$(r+s)^\ast = r^\ast + s^\ast$$r^\ast s^\ast = r^\ast+s^...
41 votes
5 answers
95
A finite state machine with the following state table has a single input $x$ and a single out $z$.$$\begin{array}{|c|ll|}\hline\textbf{present state} & \qquad \textbf{nex...
41 votes
7 answers
98
41 votes
1 answer
100
The language accepted by a Pushdown Automaton in which the stack is limited to $10$ items is best described asContext freeRegularDeterministic Context freeRecursive