  Information geometry is used to quantify the amount of information
integration within multiple terminals of a causal dynamical system. Integrated
information quantifies how much information is lost when a system is split into
parts and information transmission between the parts is removed. Multiple
measures have been proposed as a measure of integrated information. Here, we
analyze four of the previously proposed measures and elucidate their relations
from a viewpoint of information geometry. Two of them use dually flat manifolds
and the other two use curved manifolds to define a split model. We show that
there are hierarchical structures among the measures. We provide explicit
expressions of these measures.
