1
GATE CSE 2025 Set 1
MCQ (Single Correct Answer)
+1
-0.33

Consider the following context-free grammar $G$, where $S, A$, and $B$ are the variables (nonterminals), $a$ and $b$ are the terminal symbols, $S$ is the start variable, and the rules of $G$ are described as:

$$\begin{aligned} & S \rightarrow a a B \mid A b b \\ & A \rightarrow a \mid a A \\ & B \rightarrow b \mid b B \end{aligned}$$

Which ONE of the languages $L(G)$ is accepted by $G$ ?

A
$L(G)=\left\{a^2 b^n \mid n \geq 1\right\} \cup\left\{a^n b^2 \mid n \geq 1\right\}$
B
$L(G)=\left\{a^n b^{2 n} \mid n \geq 1\right\} \cup\left\{a^{2 n} b^n \mid n \geq 1\right\}$
C
$L(G)=\left\{a^n b^n \mid n \geq 1\right\}$
D
$L(G)=\left\{a^{2 n} b^{2 n} \mid n \geq 1\right\}$
2
GATE CSE 2025 Set 1
MCQ (Single Correct Answer)
+1
-0

A regular language $L$ is accepted by a non-deterministic finite automaton (NFA) with $n$ states. Which of the following statement(s) is/are FALSE?

A
$L$ may have an accepting NFA with $< n$ states.
B
$L$ may have an accepting DFA with $< n$ states.
C
There exists a DFA with $\leq 2^n$ states that accepts $L$.
D
Every DFA that accepts $L$ has $>2^n$ states.
3
GATE CSE 2025 Set 1
MCQ (Single Correct Answer)
+2
-0

Consider the following two languages over the alphabet $\{a, b\}$ :

$$\begin{aligned} & L_1=\left\{\alpha \beta \alpha \mid \alpha \in\{a, b\}^{+} \text {AND } \beta \in\{a, b\}^{+}\right\} \\ & L_2=\left\{\alpha \beta \alpha \mid \alpha \in\{a\}^{+} \text {AND } \beta \in\{a, b\}^{+}\right\} \end{aligned}$$

Which ONE of the following statements is CORRECT?

A
Both $L_1$ and $L_2$ are regular languages.
B
$L_1$ is a regular language but $L_2$ is not a regular language.
C
$L_1$ is not a regular language but $L_2$ is a regular language.
D
Neither $L_1$ nor $L_2$ is a regular language.
4
GATE CSE 2025 Set 1
MCQ (Single Correct Answer)
+2
-0

Consider the following two languages over the alphabet $\{a, b, c\}$, where $m$ and $n$ are natural numbers.

$$\begin{aligned} & L_1=\left\{a^m b^m c^{m+n} \mid m, n \geq 1\right\} \\ & L_2=\left\{a^m b^n c^{m+n} \mid m, n \geq 1\right\} \end{aligned}$$

Which ONE of the following statements is CORRECT?

A
Both $L_1$ and $L_2$ are context-free languages.
B
$L_1$ is a context-free language but $L_2$ is not a context-free language.
C
$L_1$ is not a context-free language but $L_2$ is a context-free language.
D
Neither $L_1$ nor $L_2$ are context-free languages.
EXAM MAP