Which of the following problems are decidable? 1) Does a given program ever produce an output? 2) If $L$ is a context-free language, then, is $\overline{L}$ also context-free? 3) If $L$ is a regular language, then, is $\overline{L}$ also regular? 4) If $L$ is a recursive language, then, is $\overline{L}$ also recursive?

Which of the following problems are decidable? 1) Does a given program ever produce an output? 2) If L is a context-free language, then, is L also context-free? 3) If L is a regular language, then, is L also regular? 4) If L is a recursive language, then, is L also recursive?

Topic-wise GATE CS PYQs with verified steps