1 votes 1 votes For even no a's RE over {a,b} 1) (b*ab*ab*)* + b* 2) (b*ab*ab*)*.b* 3) both are equal? which one is correct? Theory of Computation theory-of-computation finite-automata regular-expression + – dyadav335 asked Aug 14, 2017 • edited Aug 14, 2017 by dyadav335 dyadav335 2.4k views answer comment Share Follow See all 7 Comments See all 7 7 Comments reply AnilGoudar commented Aug 14, 2017 reply Follow Share 1 is correct from the dfa 0 votes 0 votes stblue commented Aug 14, 2017 reply Follow Share @AnilGoudar what's the problem in 2 ?? 0 votes 0 votes stblue commented Aug 14, 2017 reply Follow Share But we have to look for RE which generate even number of a's, ex aabbb is acceptable since it contain even number of a's, and both RE are capable of generating aabbb 0 votes 0 votes rahul sharma 5 commented Aug 14, 2017 reply Follow Share My bad!!! I read the question wrong. 0 votes 0 votes Shubhanshu commented Aug 14, 2017 reply Follow Share both are same and can be used for generating even no of a's. 1 votes 1 votes AnilGoudar commented Aug 15, 2017 reply Follow Share Yes Both are same, accepts the even number of a's but the second RE also tries to accept of any number of b's due to concatenation. Sry fr the wrong ans 0 votes 0 votes Sumit Singh Chauhan commented Aug 15, 2018 reply Follow Share Both are same. multiple expression are possible for any given language. 0 votes 0 votes Please log in or register to add a comment.
3 votes 3 votes $(b^*ab^*ab^*)^*+b^* \equiv (b^*ab^*ab^*)^*b^* \equiv b^*(b^*ab^*ab^*)^* \equiv b^*(ab^*ab^*)^* \equiv (b^*ab^*a)^*b^*$ Praveen Saini answered Aug 14, 2017 Praveen Saini comment Share Follow See all 0 reply Please log in or register to add a comment.