2 votes 2 votes CONSIDER THE FLLOWING LANGUAGE L={<M>| M is a TM and L(M)=empty} Which of the following is true? a- Decidable REC B- Undecidable and RE c-Undecidable and non RE d- Decidable but RE Theory of Computation decidability theory-of-computation recursive-and-recursively-enumerable-languages + – bts1jimin asked Jan 8, 2019 bts1jimin 618 views answer comment Share Follow See all 10 Comments See all 10 10 Comments reply Shobhit Joshi commented Jan 8, 2019 reply Follow Share $C\,?$ 0 votes 0 votes pawan kumarln commented Jan 8, 2019 reply Follow Share @Shobhit Joshi how you will prove not RE 0 votes 0 votes Shobhit Joshi commented Jan 8, 2019 reply Follow Share $L_1=\left \{ \right \} = yes, L_2 = \left\{ 1,2,3\right \}=no$ as $L_1$ is empty and $L_2$ is not empty and $L_1\subset L_2$, as empty set is subset of every set. So, it is a non-monotonic property as $yes\subset no$. Hence, $non-RE$ 1 votes 1 votes bts1jimin commented Jan 8, 2019 reply Follow Share Can you post where to read about non monotonic property and non RE? @Shobhit Joshi 0 votes 0 votes Shobhit Joshi commented Jan 8, 2019 reply Follow Share https://gatecse.in/rices-theorem/ 0 votes 0 votes bts1jimin commented Jan 8, 2019 reply Follow Share Thank you. @Shobhit Joshi Also, can you help me answer this Is maximum(plural maxima) function's maximum value or point at which function gets maximum value? Ques- f(x)=(x^2-9)^2 where x is a real number. The function has 1-Only one minimum 2- Only two minima 3- three mimima 4- three maxima 0 votes 0 votes Shobhit Joshi commented Jan 9, 2019 reply Follow Share @bts1jimin maximum value should be the maximum value that the function attains(that's what i think should be the general meaning). Here, with maximum or minimum what i think they mean is the point of local maximum and local minimum. Is the answer, only two minimum ? 0 votes 0 votes bts1jimin commented Jan 9, 2019 reply Follow Share Yes, but I dont understand why According to wikipedia, minima is minimum value of the function. See- https://en.wikipedia.org/wiki/Maxima_and_minima 0 votes 0 votes Shobhit Joshi commented Jan 9, 2019 reply Follow Share normally we consider local unless stated explicitly 0 votes 0 votes bts1jimin commented Jan 9, 2019 reply Follow Share Yes but my questiom here is, according to wikipedia minima is function's minimum value, not the points where minimum is achieved , in this question minimum value of function is 0 that is only 1 minima(at -3,+3).....but the answer is 2 minima 0 votes 0 votes Please log in or register to add a comment.