3 votes 3 votes Theory of Computation theory-of-computation context-free-language + – pranab ray asked Dec 11, 2017 pranab ray 702 views answer comment Share Follow See all 12 Comments See all 12 12 Comments reply Show 9 previous comments Ashwin Kulkarni commented Dec 11, 2017 reply Follow Share @nitish how we can write L1? L1 = {anbn n>=0} - {a5nb5n n>=0} ? But then CFL are not closed under set difference. 0 votes 0 votes joshi_nitish commented Dec 11, 2017 reply Follow Share @Ashwin, not closed under set difference means that atleast one language is not closed on set difference, it does not mean that every language is not closed, above statement means that CFL on operating under set difference may or may not be CFL, but for above case it is CFL. 1 votes 1 votes Nitesh Choudhary commented Dec 13, 2017 reply Follow Share First one is CSL 0 votes 0 votes Please log in or register to add a comment.