PyQdeck LogoPyQdeckSubjects
Back to the 2025 paper

Module 2: Context-Free Languages (CFL) and PDA

20252m

Context-free languages are NOT closed under

(i) Union
(ii) Concatenation
(iii) Intersection
(iv) Kleene star

Search GoogleAsk AI

Similar questions

Formal Language & Automata TheoryIf L1 and L2 are context-free languages, L1-L2 is \_\_\_\_ context-free. (i) always (ii) sometimes (iii) never (iv) None of the above20212mFormal Language & Automata TheoryA language accepted by deterministic pushdown automata is closed under which of the following? (i) Complement (ii) Union (iii) Both (i) and (ii) (iv) None of the above20202mFORMAL LANGUAGE & AUTOMATA THEORYWhich one of the following statements is true? (i) The intersection of two CFLs is context-free (ii) Every CFL can be accepted by a DPDA (iii) The union of two CFLs is context-free (iv) The complement of a CFL is context-free20232mFORMAL LANGUAGE & AUTOMATA THEORYA language accepted by deterministic pushdown automata is closed under which of the following? (i) Complement (ii) Union (iii) Both (i) and (ii) (iv) None of the above20232m
PreviousWhich of the following languages is NOT regular? (i) {a^n b^n | n \ge 0} (ii) {a, b}* (iii) Finite languages (iv) Languages accepted by DFANextWhich production is not allowed in a CSG? (i) AB \rightarrow BA (ii) A \rightarrow \epsilon (iii) A \rightarrow a (iv) a B \rightarrow a b