2 votes 2 votes $xwxw^r |\ w,x \in (a,b)^*$ $wxw^{r}x |\ w,x \in (a,b)^*$ Theory of Computation theory-of-computation regular-language + – Anjan asked Jan 31, 2018 Anjan 366 views answer comment Share Follow See all 5 Comments See all 5 5 Comments reply Show 2 previous comments Shubhanshu commented Jan 31, 2018 reply Follow Share But that will only accept ww^r, but not for when x is not $\in$. Eg:- aabbabaabbab now here w = w^r = $\in$ and x = aabbab, such strings will not be in your answer. 1 votes 1 votes Ajay Jadhav commented Jan 31, 2018 reply Follow Share If we treat w as epsilon it still has double x and xx is not even CFL 0 votes 0 votes Ashwin Kulkarni commented Jan 31, 2018 reply Follow Share Yes both CSL 0 votes 0 votes Please log in or register to add a comment.