  The process of equilibration of a colliding hard-disks system is studied in
the framework of classical mechanic. The method consists of dividing the
nonequilibrium system into the interacting subsystems; the evolution one of
these subsystems is analyzed employing generalized Lagrange and Liouville
equations. The subsystem-subsystem interaction force is considered as an
evolution parameter. The mechanism by which its system equilibrates is
described.
