  The number of isolating integrals of motion of the Trappist-1 system - a late
M-dwarf orbited by seven Earth-sized planets - was determined numerically,
using an adapted version of the correlation dimension method. It was found that
over the investigated time-scales of up to 20 000 years the number of isolating
integrals of motion is the same as one would find for a system of seven
non-interacting planets - despite the fact that the planets in the Trappist-1
system are strongly interacting. Considering perturbed versions of the
Trappist-1 system shows that the system may occupy an atypical part of
phase-space with high stability. These findings are consistent with earlier
studies.
