Consider the following statements:
1. The complement of every Turning decidable language is Turning decidable 2. There exists some language which is in NP but is not Turing decidable 3. If L is a language in NP, L is Turing decidable
Which of the above statements is/are True?
Only 1 and 2
Only 1 and 3
1 is true: Complement of Turing decidable is Turing Decidable. 3 is true. All NP problems are Turing decidable (See http://www.geeksforgeeks.org/np-completeness-set-1/) 2 is false: The definition of NP itself says solvable in polynomial time using non-deterministic Turing machine.