pda
GATE CSE & IT · Context-Free Languages · 1992-2026
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Hopcroft-Ullman / Dragon Book
Automata, languages, parsing, syntax-directed translation
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All concepts →Let $\Sigma=\{a, b, c, d\}$ and let $L=\left\{a^i b^j c^k d^l \mid i, j, k, l \geq 0\right\}$. Which of the following constraints ensure(s) that the language $L$ is context-free?
Consider the following two languages over the alphabet $\{a, b, c\}$, where $m$ and $n$ are natural numbers. $$\begin{aligned} & L_1=\left\{a^m b^m c^{m+n} \mid m, n \geq 1\right\}...
Which one of the following languages over $\Sigma=\{a, b\}$ is NOT context-free?
Which of the following languages are context-free? $$$\eqalign{ & {L_1} = \left\{ {{a^m}{b^n}{a^n}{b^m}|m,n \ge 1} \right\} \cr & {L_2} = \left\{ {{a^m}{b^n}{a^m}{b^n}|m,n \ge 1} \...
Consider the languages $$$\eqalign{ & {L_1} = \left\{ {{0^i}{1^j}\,\left| {i \ne j} \right.} \right\},\,{L_2} = \left\{ {{0^i}{1^j}\,\left| {i = j} \right.} \right\}, \cr & {L_3} =...
Which one of the following is FALSE?
The language accepted by a pushdown Automation in which the stack is limited to $$10$$ items is best described as
Let $${L_D}$$ be the set of all languages accepted by a $$PDA$$ by final state and $${L_E}$$ the set of all languages accepted by empty stack. Which of the following is true?
Regarding the power of recognition of languages, which of the following statement is false?
In which of the cases stated below is the following statement true? “For every non-deterministic machine $${M_1}$$ there exists an equivalent deterministic machine $${M_2}$$ recogn...