In (7.6), a correct estimate 
enables the
to be encoded as the global energy minimum for this particular
pair 
. Therefore, it makes any energy change due to a
configuration change from 
to 
positive, that is,
where
is the set of all non-
configurations. Let
be the set of all correct estimates. The set, if non-empty, usually comprises not just a single point but a region in the allowable parameter space. Some of the points in the region are better in the sense of stability to be defined below.
