# NP (complexity)
#computer-science
> NP is the set of decision problems for which the problem instances, where the answer is "yes", have proofs verifiable in polynomial time.
There exists a verifier which can checks a solution is correct in polynomial time.
> The complexity class co-NP for which the answer “no” can be verified in polynomial time.
Verifier which checks the answer is wrong in polynomial time.
📖 [NP (complexity) - Wikipedia](https://en.wikipedia.org/wiki/NP_(complexity))