Difference between revisions of "P versus NP problem"

Revision as of 19:18, 16 May 2016

The P versus NP problem is a major unsolved problem in computer science.

Informally speaking, it asks whether every problem whose solution can be quickly verified by a computer can also be quickly solved by a computer.

Description

It was essentially first mentioned in a 1956 letter written by Kurt Gödel to John von Neumann.

Gödel asked whether a certain NP-complete problem could be solved in quadratic or linear time (see Time complexity).

The precise statement of the P versus NP problem was introduced in 1971 by Stephen Cook in his seminal paper "The complexity of theorem proving procedures" and is considered by many to be the most important open problem in the field.

It is one of the seven Millennium Prize Problems selected by the Clay Mathematics Institute to carry a US$1,000,000 prize for the first correct solution.

Quickly

The informal term quickly, used above, means the existence of an algorithm for the task that runs in polynomial time, i.e., that the time to complete the task varies as a polynomial function on the size of the input to the algorithm (as opposed to, say, exponential time).

The general class of questions for which some algorithm can provide an answer in polynomial time is called "class P" or just "P".

For some questions, there is no known way to find an answer quickly, but if one is provided with information showing what the answer is, it is possible to verify the answer quickly.

The class of questions for which an answer can be verified in polynomial time is called NP, which stands for "nondeterministic polynomial time."

See also

• Computer science
• Computation
• Game complexity
• Time complexity
• Unique games conjecture
• Unsolved problems in computer science
• Unsolved problems in mathematics

External links

• P versus NP problem @ Wikipedia