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.
What is Decidability in theory of computation?
A language is called Decidable or Recursive if there is a Turing machine which accepts and halts on every input string w. Every decidable language is Turing-Acceptable. A decision problem P is decidable if the language L of all yes instances to P is decidable.
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 halting problem in automata?
The Halting Problem is the problem of deciding or concluding based on a given arbitrary computer program and its input, whether that program will stop executing or run-in an infinite loop for the given input.
What is Decidability in theory of automata write down the steps for finding whether two languages are equivalent or not?
Hence, the state entry problem is undecidable. 2. Given two regular languages L1 and L2, is the problem of finding whether a string ‘w’ exists in both L1 and L2, a decidable problem or not. First we make two Turing machines TM1 and TM2 which simulate the DFAs of languages L1 and L2 respectively.
What do you mean by Decidability?
capable of being decided
: capable of being decided specifically : capable of being decided as following or not following from the axioms of a logical system Was logic complete …? And was it decidable, in the sense that there was a method that demonstrated the truth or falsity of every statement? —
Is the halting problem computable?
Example: The halting problem is partially computable. To determine HALTS(P,D), simply call P(D). Then, HALTS(P,D) halts and outputs Yes if P(D) halts, and loops otherwise.
What is Decidability closed under?
– Decidable languages are closed under complementation. To design a machine for the complement of a language L, we can simulate the machine for L on an input. If it accepts then accept and vice versa. – Turing recognizable languages are not closed under complement.
What is the Decidability problem?
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.
Why is Decidability important?
A language is decidable If a TM recognises the language and goes into an Accept or Reject state. As a dev. I think this is important as it would mean we could determine if a program contains buffer overflows or deadlocks.
When can you not use Rice’s theorem?
Similarly, whether a machine has more than 5 states is a decidable property of the machine, as the number of states can simply be counted. For properties of this kind, which concerns a Turing machine but not the language recognized by it, Rice’s Theorem does not apply.