On Fri, 2016-02-19 at 15:45 +0000, Simon Hobson wrote:
> Rainer Weikusat <rainerweikusat@???> wrote:
>
> > The abstract definition of 'runlevel' is (as far as I'm aware of it):
> > "Set of processes supposed to be running".
>
> That's what I understand it to be.

FYI: You might be interested in the problem of defining runlevels. Here is a
historical note (from the shepherd manual):

https://www.gnu.org/software/shepherd/manual/html_node/Runlevel-evolution.html#R
unlevel-evolution

Probably runlevels can be stated as a mathematical problem to solve. Has anybody
seen such an attempt somewhere?