It is felt that the problem of selecting the structure of
interconnections for a network is intimately connected to the
previously mentioned problem of generalization. Presumably a given
type of generalization can be obtained by providing appropriate fixed
portions of the network and an appropriate interconnection structure
for the variable portion. However, for very large networks, it is
undoubtedly necessary to restrict the complexity so that it can be
specified by relatively simple rules. Since very little is known about
this quite important problem, no further discussion will be attempted
here.