1 votes 1 votes closed as a duplicate of: if $w \in (a+b)^*$ satisfies $abw = wab$, then $\text{length}(w)$ is ? $\epsilon$ monali asked Nov 24, 2015 • closed Nov 24, 2015 by Digvijay Pandey monali 305 views comment Share Follow See all 0 reply Please log in or register to add a comment.