Syntax
where B is the name of a base or element.
The CENTRE: command is used to transform cross product belief
specifications into covariances. That is, for each pair of elements
and 
in B, and for each of the unlocked belief
stores, S, the current value stored for the specification over the
pair 
is replaced by this value minus the product of the
respective expectations for and . This command should be
used when a set of belief specifications is given in the form 
rather than the form 
, where
and 
are vectors of unknowns.
See §6.2 for
details of specifying collections for the definition part.
