  Using properties of Blum complexity measures and certain complexity class
operators, we exhibit a total computable and non-decreasing function
$t_{\mathsf{poly}}$ such that for all $k$, $\Sigma_k\mathsf{P} =
\Sigma_k\mathsf{TIME}(t_{\mathsf{poly}})$, $\mathsf{BPP} =
\mathsf{BPTIME}(t_{\mathsf{poly}})$, $\mathsf{RP} =
\mathsf{RTIME}(t_{\mathsf{poly}})$, $\mathsf{UP} =
\mathsf{UTIME}(t_{\mathsf{poly}})$, $\mathsf{PP} =
\mathsf{PTIME}(t_{\mathsf{poly}})$, $\mathsf{Mod}_k\mathsf{P} =
\mathsf{Mod}_k\mathsf{TIME}(t_{\mathsf{poly}})$, $\mathsf{PSPACE} =
\mathsf{DSPACE}(t_{\mathsf{poly}})$, and so forth. A similar statement holds
for any collection of language classes, provided that each class is definable
by applying a certain complexity class operator to some Blum complexity class.
