Figure 2. Probability distributions of the scores
of
vertices external to a given subgraph 
of the
graph.
The score 
is the
-th
smallest score of the external vertices. In this particular case there
are 
external vertices. In the figure, we plot
,
,
,
,
(from left
to right). As an example, the shaded areas show the cumulative
probability 
for a few
values of 
that would
correspond to the values estimated in a practical situation. In this
case, the black area, 
, is the
least extensive and so 
. If
, the
vertices with scores 
,
,
and
will be
added to 
.