0 votes 0 votes Shadan Karim asked Dec 22, 2018 Shadan Karim 237 views answer comment Share Follow See all 3 Comments See all 3 3 Comments reply Shubhgupta commented Dec 22, 2018 reply Follow Share should be D. 0 votes 0 votes Hemanth_13 commented Dec 22, 2018 i edited by Hemanth_13 Dec 22, 2018 reply Follow Share a) $\sum^* - a^nb^n$ -> it is NPDA acceptable. b)$\sum^* \bigcap a^nb^nc^m$==> $a^nb^nc^m\bigcup a^nb^nc^n$ ==>$a^nb^nc^{m+n}$--> not DCFL c is also true $\sum^*- L3$ =L3` => L3 is closed under complement so its is CSL @Shubhgupta please correct me if I'm wrong? 0 votes 0 votes Shubhgupta commented Dec 22, 2018 reply Follow Share 1) how are you sure that difference will be NPDA? Can you tell the language? I did with theory that every regular is DCFL so CFL and DCFL is also CFL and CFL is not closed under set difference then cannot be CFL. 2) Its union will be $a^{n}b^{n}c^{n+m}$ clearly not DCFL moreover you selected L3 as CSL but it is recursive in question. 3) L3 is recursive and recursive are closed under complement so it should be recursive not CSL. 0 votes 0 votes Please log in or register to add a comment.