0 votes 0 votes Equality problem for language L1 and L2, L1 =L2 or L1 ≠ L2 For which of the following class language equality problem is decidable a. Regular b. CFL c. CSL d. REC e. RE Theory of Computation theory-of-computation + – Satyajeet Singh asked Sep 15, 2017 Satyajeet Singh 978 views answer comment Share Follow See all 6 Comments See all 6 6 Comments reply Show 3 previous comments Satyajeet Singh commented Sep 16, 2017 reply Follow Share Correct .. nice explanation. Btw which source you follow for studying undecidability topic.. i tried Peter Linz but there is no specify chapter for this topic. Rice theorem and all are not given in it. Recommend some source . 0 votes 0 votes prateekdwv commented Sep 16, 2017 reply Follow Share IMHO, refer Introduction to Theory of Computation Michael Sipser for advance topics of this subject. Video lectures of Shai Simonson are also very good. Rest all depends on practice, I guess. 1 votes 1 votes surbhijain93 commented Sep 9, 2018 reply Follow Share @prateekdww Please correct me if wrong Your logic is valid for equality but not for complementation, complement of CFL is undecidable but still is decidable for CSL/REC cause complement of CFL is CSL at the most cause CSL is closed under complementation. But since there is no such point for equality, therefore CSL/REC are not decidable in equality. Right? 0 votes 0 votes Please log in or register to add a comment.