What's the relationship of $n^n$ and $n!$ complexity with respect to EXPTIME?

Question

We know that:

• $k^n = o(n!)$
• $n! = o(n^n)$

where $o$ refers to "little o notation" (i.e. bounds that are asymptotically not tight).

With that in mind:

• Are there any defined or academically established classes for problems with complexity of at most $O(n!)$ and $O(n^n)$?
• What is the set relationship for these classes of problems with respect to $\mathsf{EXPTIME}$ or e.g. $\mathsf{2\mbox{-}EXPTIME}$?

Answer 1

$\mathsf{EXPTIME}$ is the class of problems solvable by algorithms whose running time is $O(2^{n^c})$ for some $c>0$. In contrast, $\mathsf{E}$ is the class of problems solvable by algorithms whose running time is $O(2^{cn})$ for some $c>0$.

These definitions show that problems solvable in time $O(n!)$ or $O(n^n)$ are in $\mathsf{EXPTIME}$, but not necessarily in $\mathsf{E}$.