2 votes 2 votes L={<M>: M is a TM that accepts all even numbers } Why it is not recursively enumerable language??? Theory of Computation rice-theorem theory-of-computation decidability + – akb1115 asked Jul 18, 2017 akb1115 772 views answer comment Share Follow See all 4 Comments See all 4 4 Comments reply srestha commented Jul 18, 2017 reply Follow Share Actually there are infinite number of even numbers. So, yes cases of this language form a loop. This language produce loop in 'yes' cases of the language, so we can say yes case is not satisfied here.That is why it is non R.E. 2 votes 2 votes akb1115 commented Jul 18, 2017 reply Follow Share "So, yes cases of this language form a loop" Can you please elaborate this line a bit more 0 votes 0 votes akb1115 commented Jul 19, 2017 reply Follow Share @srestha So do you want to say that complement of halting problem(i.e given an input w whether the Turing machine will go into an infinite loop or not) which is completely undecidable can be reduced to this given problem???? Which will make this problem undecidable. 0 votes 0 votes set2018 commented Nov 2, 2017 reply Follow Share but we have enumeration method for this .According to that it must be recursive enumerable akb1115 srestha 0 votes 0 votes Please log in or register to add a comment.