Question 42Asked in BEL PE Computer Science, 20 Dec 2025 (5:00 PM)

Let Σ = {a, b}. Define: R₁ = (a + b) b (a + b)

Let Σ = {a, b}. Define: R₁ = (a + b) b (a + b) R₂ = (a + b) a (a + b) R₃ = (a + b) b (a + b)** R₄ = (a + b) (aa + bb) (a + b)* Define F(R) as the language denoted by R using the usual recursive rules: F(a) = {a}, F(b) = {b}, F(ε) = {ε} F(R1 + R2) = F(R1) ∪ F(R2) F(R1R2) = F(R1) · F(R2) F(R)* = (F(R))* Which of the following statements about the equivalence of these regular expressions is true?
  1. AF(R₁) ∪ F(R₂) = Σ².
  2. BF(R₄) ⊆ F(R₃).
  3. CF(R₃) = Σ* \ a*
  4. DF(R₁) = F(R₂)
Show answerHide answer

Correct answer: (C) F(R₃) = Σ* \ a*

From BEL PE Computer Science PYQ, 20 Dec 2025 (5:00 PM)

This is question 42 of BEL PE Computer Science PYQ, 20 Dec 2025 (5:00 PM). See all questions of this paper with answers, or attempt the paper as a timed online test to get your score and all-India rank.