# What does post correspondence problem mean?

## What does post correspondence problem mean?

Post Correspondence Problem is a popular undecidable problem that was introduced by Emil Leon Post in 1946. It is simpler than Halting Problem. In this problem we have N number of Dominos (tiles). The aim is to arrange tiles in such order that string made by Numerators is same as string made by Denominators.

How do you find the post correspondence solution?

Post Correspondence Problem

1. Solution:
2. Solution: Now we have to find out such a sequence that strings formed by x and y are identical. Such a sequence is 1, 2, 1, 3, 3, 4.
3. Solution: Consider the sequence 1, 3, 2. The string obtained from A = babababb.
4. Solution: The solution is 1, 3, 1, 1, 3, 2, 2. The string is.

### What is Mpcp in TOC?

Modified Post Correspondence Problem (MPCP) Definition: first pair in the A and B lists must be the first pair in the solution, i.e., the problem is to determine if there is a sequence of zero or more integers i1, i2, …, im such that: w1wi1 wi2 … wim = x1xi1 xi2 …

Is post correspondence Decidable?

Introduction: The Post’s Correspondence Problem is an undecidable decision problem that was introduced by “ Emil Leon Post ” in 1946. Our goal is to prove this problem about strings to be undecidable, and then use its Un-decidability to prove other problems undecidable by reducing PCP to those.

## Why is post correspondence problem undecidable?

The Post correspondence problem is an undecidable decision problem that was introduced by Emil Post in 1946. Because it is simpler than the halting problem and the Entscheidungsproblem it is often used in proofs of undecidability.

What makes a problem undecidable?

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.