What is not computable?
A non-computable is a problem for which there is no algorithm that can be used to solve it. Most famous example of a non-computablity (or undecidability) is the Halting Problem.
What does it mean for a problem to be decidable?
(definition) Definition: A decision problem that can be solved by an algorithm that halts on all inputs in a finite number of steps. The associated language is called a decidable language. Also known as totally decidable problem, algorithmically solvable, recursively solvable.
Which of the following is are Undecidable?
Which of the following is/are undecidable? Explanation: First is Emptiness for CFG; whether a CFG is empty or not, this problem is decidable. Second is everything for CFG; whether a CFG will generate all possible strings (completeness of CFG), this problem is undecidable.
Which of the following problems is are Undecidable?
Which of the following problems is undecidable? Deciding if a given context-free grammar is ambiguous. Deciding if a given string is generated by a given context-free grammar. Deciding if the language generated by a given context-free grammar is empty.
Which of the following is are Undecidable G is a CFG?
Correct Option: D 2. G is a CFG.
What do we call a problem if it has an algorithm to answer it?
Explanation: A problem is called intractable iff there is an efficient (i.e. polynomial time) algorithm that solves it. Explanation: A language is recursive if there exists a turing machine such that it halts i.e. accepts if the input belongs to the language else rejects. It is better called Turing decidable language.
Is halting problem in NP?
It is also easy to see that the halting problem is not in NP since all problems in NP are decidable in a finite number of operations, but the halting problem, in general, is undecidable.
Where is Turing machine now?
The National Museum of Computing