0
Add your answer:
Earn +20 pts
What are some examples of undecidable languages and how are they different from decidable languages?
Undecidable languages are languages for which there is no algorithm that can determine whether a given input string is in the language or not. Examples of undecidable languages include the Halting Problem and the Post Correspondence Problem. Decidable languages, on the other hand, are languages for which there exists an algorithm that can determine whether a given input string is in the language or not. Examples of decidable languages include regular languages and context-free languages. The key difference between undecidable and decidable languages is that decidable languages have algorithms that can always provide a definite answer, while undecidable languages do not have such algorithms.
Is the halting problem NP-hard?
Yes, the halting problem is not NP-hard, it is undecidable.
What is the decidable problem definition in computer science?
In computer science, a decidable problem is one that can be solved by an algorithm that always halts and gives a correct answer. This means that there is a clear and definite method to determine the solution to the problem.
Is the halting problem undecidable?
Yes, the halting problem is undecidable, meaning that there is no algorithm that can determine whether a given program will halt or run indefinitely.
What are the closure properties of decidable languages?
Decidable languages are closed under union, intersection, concatenation, and Kleene star operations. This means that if two languages are decidable, their union, intersection, concatenation, and Kleene star are also decidable.
Is the halting problem NP-hard?
Yes, the halting problem is not NP-hard, it is undecidable.
Is the halting problem undecidable?
Yes, the halting problem is undecidable, meaning that there is no algorithm that can determine whether a given program will halt or run indefinitely.
What did Alan turing do for the computer?
proved "the halting problem" was false.
Define formally Turing-Decidable Problem?
define function formally and using f(x) notation
Are decidable languages closed under any operations?
Yes, decidable languages are closed under operations such as union, intersection, concatenation, and complementation. This means that if a language is decidable, performing these operations on it will result in another decidable language.
What are the advantage and disadvantage of predicate logic?
Advantage:• Much more sophisticated than Source Language (SL). Can capture much (but not all) ofnatural language.Disadvantage:• Not decidable. In computability theory and computational complexity theory, an undecidable problem is a decision problem for which it is impossible to construct a single algorithm that always leads to a correct yes-or-no answer.A decision problem is any arbitrary yes-or-no question on an infinite set of inputs. Because of this, it is traditional to define the decision problem equivalently as the set of inputs for which the problem returns yes. These inputs can be natural numbers, but also other values of some other kind, such as strings of a formal language. Using some encoding, such as a Godel numbering, the strings can be encoded as natural numbers. Thus, a decision problem informally phrased in terms of a formal language is also equivalent to a set of natural numbers. To keep the formal definition simple, it is phrased in terms of subsets of the natural numbers.Formally, a decision problem is a subset of the natural numbers. The corresponding informal problem is that of deciding whether a given number is in the set. A decision problem A is called decidable or effectively solvable if A is a recursive set. A problem is called partially decidable, semi-decidable, solvable, or provable if A is a recursively enumerable set. Partially decidable problems and any other problems that are not decidable are called undecidable.
Are decidable languages closed under concatenation?
Yes, decidable languages are closed under concatenation.
Are decidable languages closed under intersection?
Yes, decidable languages are closed under intersection.
Can you provide proof of the halting problem?
The halting problem is a fundamental issue in computer science that states it is impossible to create a program that can determine if any given program will halt or run forever. This was proven by Alan Turing in 1936 through his concept of a Turing machine. The proof involves a logical contradiction that arises when trying to create such a program, showing that it is not possible to solve the halting problem for all cases.
Q.If a language is decidable and Turing recognizable then prove that it is also co Turing?
Turing Decidable Languages are both Turing Rec and Turing Co-Recognizable. If a Language is Not Turing Decidable, either it, or it's complement, must be not Recognizable.
Is it possible to show that the language recognized by an infinite pushdown automaton is decidable?
No, it is not possible to show that the language recognized by an infinite pushdown automaton is decidable.
What is universal turing machine and halting problem?
Universal Turing machine (UTM) is machine which can simulate any other TM, thus can compute anything computable Halting problem: given randomly chosen TM with finite randomly chosen input tape, decide that this machine will ever halt (i.e. reach state which never changes, doesn't change tape or move TM head). Halting problem for arbitrary TM was proven undecidable
