  In high energy hadron-hadron and e+e- collisions, to isolate a part of the
phase space in multi-hadron final states is necessary for exploring the
underlying dynamics. It is shown that the partition of phase space according to
the value of rapidity, popularly used in hadron-hadron collisions, is
inappropriate for the study of e+e- collisions. The proper way in the latter
case is to identify the visible jets and take them as objects for detailed
study, forming an extended phase space. The value y_cut^(0) of the
distance-measure for the identification of visible jets is determined. A new
variable $r$ is introduced to further partition the phase space inside jets,
which possesses a very good anomalous scaling property, showing that the
$r$-distribution inside jets is a self-similar fractal.
