What is undecidable in Turing machine?
For an undecidable language, there is no Turing Machine which accepts the language and makes a decision for every input string w (TM can make decision for some input string though). A decision problem P is called “undecidable” if the language L of all yes instances to P is not decidable.
How do you prove that a Turing machine is undecidable?
For a correct proof, need a convincing argument that the TM always eventually accepts or rejects any input. How can you prove a language is undecidable? To prove a language is undecidable, need to show there is no Turing Machine that can decide the language. This is hard: requires reasoning about all possible TMs.
What is undecidable problem how it can be solved?
In computability theory, an undecidable problem is a type of computational problem that requires a yes/no answer, but where there cannot possibly be any computer program that always gives the correct answer; that is, any possible program would sometimes give the wrong answer or run forever without giving any answer.
Are undecidable problems unsolvable?
An undecidable problem is one for which no algorithm can ever be written that will always give a correct true/false decision for every input value. Undecidable problems are a subcategory of unsolvable problems that include only problems that should have a yes/no answer (such as: does my code have a bug?).
What is the definition of undecidable?
Definition of undecidable : not capable of being decided : not decidable … a huge popular audience, most of whom must have been baffled and exasperated by its elaborate and undecidable mystifications.—
What are undecidable problems about Turing machine?
The problems for which we can’t construct an algorithm that can answer the problem correctly in the infinite time are termed as Undecidable Problems in the theory of computation (TOC). A problem is undecidable if there is no Turing machine that will always halt an infinite amount of time to answer as ‘yes’ or ‘no’.
Does undecidable mean unrecognizable?
Undecidability means recognizable or unrecognizable.
What is an undecidable problem how is it different from a reducible problem?
What is an example of an undecidable problem?
Examples – These are few important Undecidable Problems: Whether a CFG generates all the strings or not? As a CFG generates infinite strings, we can’t ever reach up to the last string and hence it is Undecidable.
Is Fermat’s theorem undecidable?
So it looks entirely possible that it is indeed undecidable. But as for proving it, that’s a different matter. The theorem isn’t directly linked to a rapidly increasing sequence, but it might be possible to link it to such a sequence .
What problem is undecidable?
What is an undecidable problem example?
What is undecidable problem write one example how can it be solved?
A problem is undecidable if there is no Turing machine that will always halt an infinite amount of time to answer as ‘yes’ or ‘no’. The examples of undecidable problems are explained below. Here, CFG refers to Context Free Grammar.
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.
How many undecidable languages are there?
two undecidable languages
We’ve now proven the existence of two undecidable languages (ATM and ATM) and one unrecognizable language (ATM).
What is undecidable problem in computer science?
There are some problems that a computer can never solve, even the world’s most powerful computer with infinite time: the undecidable problems. An undecidable problem is one that should give a “yes” or “no” answer, but yet no algorithm exists that can answer correctly on all inputs.