Was (wer) ist Co-NP - definition
COMPLEXITY CLASS
CoNP; Co np; Co NP; NP = co-NP problem
NP-hard
![P≠NP]], while the right side is valid under the assumption that P=NP (except that the empty language and its complement are never NP-complete)](https://commons.wikimedia.org/wiki/Special:FilePath/P np np-complete np-hard.svg?width=200 "P≠NP]], while the right side is valid under the assumption that P=NP (except that the empty language and its complement are never NP-complete)")
<complexity> A set or property of computational {search
problems}. A problem is NP-hard if solving it in {polynomial
time} would make it possible to solve all problems in class
NP in polynomial time.
Some NP-hard problems are also in NP (these are called
"NP-complete"), some are not. If you could reduce an NP
problem to an NP-hard problem and then solve it in polynomial
time, you could solve all NP problems.
See also computational complexity.
[Examples? ]
(1995-04-10)
NP-hardness
In computational complexity theory, NP-hardness (non-deterministic polynomial-time hardness) is the defining property of a class of problems that are informally "at least as hard as the hardest problems in NP". A simple example of an NP-hard problem is the subset sum problem.
Wikipedia
Co-NP
In computational complexity theory, co-NP is a complexity class. A decision problem X is a member of co-NP if and only if its complement X is in the complexity class NP. The class can be defined as follows: a decision problem is in co-NP precisely if only no-instances have a polynomial-length "certificate" and there is a polynomial-time algorithm that can be used to verify any purported certificate.
That is, co-NP is the set of decision problems where there exists a polynomial and a polynomial-time bounded Turing machine M such that for every instance x, x is a no-instance if and only if: for some possible certificate c of length bounded by , the Turing machine M accepts the pair (x, c).
