Let A and B be infinite alphabets and let # be a symbol outs

General Aptitude
Computer Science & IT

M: +2.00/-0.66

Let A and B be infinite alphabets and let # be a symbol outside both A and B. Let f be a total functional from A* to B*. We say f is computable if there exists a Turning machine M which given an input x in A*, always halts with f(x) on its tape. Let L_f denote the language Which of the following statements is true:

[GATE CS 2017 Set 1]

A f if computable if and only if Lf is recursive.

B f is computable if and only Lf recursively enumerable.

C If f is computable then Lf is recursive, but not conversely.

D If f is computable then Lf is recursively enumerable, but not conversely.