Post's correspondence problem

(classic problem)

Definition: Given a set of pairs of strings, find a sequence of pairs such that the concatenation of all first members of the pairs is the same string as the concatenation of all second members. This is an undecidable problem.

Also known as PCP.

Author: SKS

More information

Ling Zhao's page with examples, notes on programs to find solutions, etc..

Emil Post, A Variant of a Recursively Unsolvable Problem. Bulletin of the American Mathematical Society, 52:264-268, 1946.

Go to the Dictionary of Algorithms and Data Structures home page.

If you have suggestions, corrections, or comments, please get in touch with Paul E. Black.

Entry modified Fri Dec 17 11:53:43 2004.
HTML page formatted Wed Oct 26 09:47:58 2005.

Cite this as:
Sandeep Kumar Shukla, "Post's correspondence problem", from Dictionary of Algorithms and Data Structures, Paul E. Black, ed., NIST.
http://www.nist.gov/dads/HTML/postsCorrespondProb.html