Inheritance Reasoning in Connectionist Networks.

We describe a bi-directional network model of inheritance reasoning which processes queries by combinations of top-down and bottom- up reasoning. The model, which is based on recent theoretical work in non-monotonic reasoning, permits multiple inheritance paths in acyclic inheritance theories and allows an arbitrary preference relation among the inferences in the theory (to handle exceptions, for example). Unlike other inheritance models which serially compute extensions (maximally consistent models), our network gains substantially more parallelism by simultaneously reasoning in multiple extensions when possible.