The well-known complexity class NP can be defined in terms of NTIME as follows:

$mbox\{NP\}\; =\; bigcup\_\{kinmathbb\{N\}\}\; mbox\{NTIME\}(n^k)$

Similarly, the class NEXPTIME is defined in terms of NTIME. The non-deterministic time hierarchy theorem says that nondeterministic machines can solve more problems in asymptotically more time.