Geometrically, the effect of the belief adjustment may be represented by the eigenstructure of a certain linear operator defined on [B]. This operator is defined to be
where , are the orthogonal projections from [D] to [B], and from [B] to [D], respectively.
is a bounded self-adjoint operator, as are adjoint transforms, namely
because both sides of the above equation are equal to (X,Y).
The operator is termed the resolution transform for B induced by D, as it represents the variance resolved for each X by D as
as
We may also evaluate the transform
where I is the identity operator on [B]. We term the variance transform for B induced by D, as adjusted covariance is represented by the relation, for each X and Y in , that
or equivalently, in terms of the inner products over [B], as
, are self-adjoint operators, of norm at most one. They have common eigenvectors, , with eigenvalues , where .
From equation 47, we may deduce that, provided has a discrete spectrum, each canonical direction, , of the adjustment of B by D, is an eigenvector of , with eigenvalue , and conversely each eigenvector of is a canonical direction of the adjustment. Thus the eigenstructure of summarises the effects of the adjustment over the whole structure [B]. In particular, the resolved uncertainty may be written as