Why do undecidable problems exist?

The halting problem. Alan Turing proved the existence of undecidable problems in 1936 by finding an example, the now famous “halting problem”: Based on its code and an input, will a particular program ever finish running? That program will halt, since num eventually becomes 0.

What is undecidable problem in automata?

Undecidable Problems A problem is undecidable if there is no Turing machine which will always halt in finite amount of time to give answer as ‘yes’ or ‘no’. An undecidable problem has no algorithm to determine the answer for a given input.

What is the halting problem of Turing machine?

The halting problem is a decision problem about properties of computer programs on a fixed Turing-complete model of computation, i.e., all programs that can be written in some given programming language that is general enough to be equivalent to a Turing machine.

Which of the following problem is 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.

What do you understand by undecidable problem prove that halting problem of Turing machine is undecidable?

The Halting Problem is Undecidable: Proof Since there are no assumptions about the type of inputs we expect, the input D to a program P could itself be a program. Compilers and editors both take programs as inputs.

How is halting problem Undecidable?

Alan Turing proved in 1936 that a general algorithm running on a Turing machine that solves the halting problem for all possible program-input pairs necessarily cannot exist. Hence, the halting problem is undecidable for Turing machines.

Why is the halting problem important?

The Halting problem lets us reason about the relative difficulty of algorithms. It lets us know that, there are some algorithms that don’t exist, that sometimes, all we can do is guess at a problem, and never know if we’ve solved it.

Which of the following problem is undecidable ambiguity?

Only ambiguity problem for CFGs are undecidable. Thus, option (B) is correct.

Which problem is undecidable Mcq?

Undecidable Problems MCQ Question 1 Detailed Solution According to Rice’s theorem, emptiness problem of Turing machine is undecidable.

What is Decidability explain in brief about any two undecidable problems?

The problems for which we can’t construct an algorithm that can answer the problem correctly in finite time are termed as Undecidable Problems. These problems may be partially decidable but they will never be decidable.