13.6 Glocal Memory 263 e in which most memory items come in pairs, consisting of one local item and one global item, so that activation of the local item (the “key”) frequently leads in the near future to activation of the global item (the “map”) Obviously, in the scope of all possible memory structures constructible within the above formalism, glocal memories are going to be very rare and special. But, we suggest that they are important, because they are generally going to be the most effective way for intelligent systems to structure their memories. Note also that many memories without glocal structure may be “well-aligned” in the above sense. An example of a predominantly local memory structure, in which nearly all significant mem- ory items are local according to the above definition, is the Cyc logical reasoning engine [LG90]. To cast the Cye knowledge base in the present formal model, the tokens are logical predicates. Cyc does not have an in-built notion of activation, but one may conceive the activation of a logical formula in Cyc as the degree to which the formula is used in reasoning or query process- ing during a certain interval in time. And one may define a basic metric for Cye by associating a predicate with its extension (the set of satisfying inputs), and defining the similarity of two predicates as the symmetric distance of their extensions. Cyc is reasonably well-aligned, but according to the dynamics of its querying and reasoning engines, it is basically a local memory structure without significant global memory structure. On the other hand, an example of a predominantly global memory structure, in which nearly all significant memory items are global according to the above definition, is the Hopfield asso- ciative memory network [Ami89]. Here memories are stored in the pattern of weights associated with synapses within a network of formal neurons, and each memory in general involves a large number of the neurons in the network. To cast the H