0 votes 0 votes Given that L1 is regular and L2 context free. i) L3 = L1 ∩ L2 ii) L4= L1.L2 Selct the most appropriate statement: a. L3 , L4 are regular b. L3 is regular L4 is CFG not regular c. L3 is CFG, not regular L4 is regular d. L3,L4 are CFG not regular Theory of Computation theory-of-computation regular-language context-free-grammar + – sh!va asked Feb 1, 2017 recategorized Jun 21, 2022 by Lakshman Bhaiya sh!va 816 views answer comment Share Follow See 1 comment See all 1 1 comment reply Sushant Gokhale commented Feb 1, 2017 reply Follow Share is it D? 0 votes 0 votes Please log in or register to add a comment.
Best answer 1 votes 1 votes Option D) is almost correct. 1) Intersection of CFL and regular is CFL but it may be regular too. For eg if L1 is $\epsilon$ which is regular then intersection of L1 with any langauage will be $\epsilon$ which is regular. So it is defintely CFL and may or may not be regular 2) Similarly concatenation is also closed for CFL. but in certain cases it may be regular. If L1 = $\phi$ then concatenation with always be phi which is regular. So both are definetely CFL and may or may not be regular. Kaushik.P.E answered Feb 1, 2017 selected Feb 1, 2017 by sh!va Kaushik.P.E comment Share Follow See all 0 reply Please log in or register to add a comment.