# What is an example of an undecidable 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. Whether two CFG L and M equal?

### What functions are not computable?

The set of finitary functions on the natural numbers is uncountable so most are not computable. Concrete examples of such functions are Busy beaver, Kolmogorov complexity, or any function that outputs the digits of a noncomputable number, such as Chaitin’s constant.

**What are decidable and undecidable problems?**

A decision problem P is undecidable if the language L of all yes instances to P is not decidable. An undecidable language may be partially decidable but not decidable. Suppose, if a language is not even partially decidable, then there is no Turing machine that exists for the respective language.

**Are all solvable problems computable?**

A mathematical problem is computable if it can be solved in principle by a computing device. Some common synonyms for “computable” are “solvable”, “decidable”, and “recursive”. Hilbert believed that all mathematical problems were solvable, but in the 1930’s Gödel, Turing, and Church showed that this is not the case.

## What problems are not computable?

Non-Computable Problems – A non-computable is a problem for which there is no algorithm that can be used to solve it. The most famous example of a non-computability (or undecidability) is the Halting Problem.

### What is Decidability problem?

(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.

**Why is busy beaver not computable?**

The busy beaver function is non-computable, because it grows faster than any computable function! Proof: Let f be any computable function. Consider M: X then MF then MF where X: blank → x 1’s. Note X has x states.

**What is the difference between an undecidable problem and an intractable problem?**

Undecidable problems are those for which no computer solution can ever exist, while intractable problems are those for which there is strong evidence that, although they can be solved by a computer, they cannot be solved sufficiently fast that the solution is truly useful in practice.

## What are tractable problems?

Tractable problem, in computational complexity theory, a problem that can be solved in polynomial time. Tractable, ease of obtaining a mathematical solution such as a closed-form expression.

### What are undecidable problems in computer science?

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.

**What is the blank tape problem?**

The problem of finding an algorithm that, for any Turing machine, decides whether the machine eventually stops if it started on an empty tape; it has been proved that no such algorithm exists.

**What is meaning of busy as a beaver?**

Hardworking, very industrious

Hardworking, very industrious, as in With all her activities, Sue is always busy as a bee, or Bob’s busy as a beaver trying to finish painting before it rains. The comparison to beavers dates from the late 1700s, the variant from the late 1300s. Also see eager beaver; work like a beaver.

## What is an example of an intractable problem?

One example of an intractable problem, you have to travel from the starting city to all cities on the map and back to the starting city, for the lowest cost.

### Which of the following are examples of intractable problems?

10.3 Examples of some Intractable Problems

- 10.3.1 Traveling Salesman Problem.
- 10.3.2 Subset Sum.
- 10.3.3 Knapsack Problem.
- 10.3.4 Bin Packing.
- 10.3.5 Job Shop Scheduling.
- 10.3.6 Satisfiability.

**What is tractable and non tractable?**

Tractable Problem: a problem that is solvable by a polynomial-time algorithm. The upper bound is polynomial. Intractable Problem: a problem that cannot be solved by a polynomial-time al- gorithm. The lower bound is exponential. • Here are examples of tractable problems (ones with known polynomial-time algo-

**What do you mean by unsolvable problems?**

(definition) Definition: A computational problem that cannot be solved by a Turing machine. The associated function is called an uncomputable function. See also solvable, undecidable problem, intractable, halting problem.

## What do we say beaver in Hindi?

beaver noun [C] (ANIMAL) an animal with smooth fur, sharp teeth, and a large, flat tail. Beavers build dams (= walls of sticks and earth) across rivers. Want to learn more?

### What do you mean by Free Bird?

free bird. One who is totally unencumbered or unrestrained by any previous obligations. I’m a free bird this Friday!

**What are tractable and non tractable problems?**

**What are intractable problems?**

From a computational complexity stance, intractable problems are problems for which there exist no efficient algorithms to solve them. Most intractable problems have an algorithm – the same algorithm – that provides a solution, and that algorithm is the brute-force search.