  The location of quantum information in various subsets of the qudit carriers
of an additive graph code is discussed using a collection of operators on the
coding space which form what we call the information group. It represents the
input information through an encoding operation constructed as an explicit
quantum circuit. Partial traces of these operators down to a particular subset
of carriers provide an isomorphism of a subgroup of the information group, and
this gives a precise characterization of what kinds of information they
contain. All carriers are assumed to have the same dimension D, an arbitrary
integer greater than 1.
