0 votes 0 votes closed as a duplicate of: GATE CSE 2003 | Question: 54 Theory of Computation theory-of-computation decidability + – nitish asked May 4, 2017 • closed May 4, 2017 by Praveen Saini nitish 297 views comment Share Follow See 1 comment See all 1 1 comment reply suryaprakash commented Jun 2, 2018 reply Follow Share option A i think RE are not closed under complements 0 votes 0 votes Please log in or register to add a comment.