Principles of Semantic Networks

Abstract

The definition of SNePS molecular nodes as cablesets captures the notion that a new arc (wire) cannot be added as emanating from an already existing node. This would amount to changing the denotation of the node. Instead, a new wire joined to an old node makes a new node that is related to the old one by the reduction relation. Similarly, a node without one or more of its wires is a new node that is a reduction of the old one. The propositions denoted by a node and a reduction of it are related by reduction inference, which is one kind of subconscious inference supported by SNePS. Path-based inference is another kind of subconscious inference that justifies belief in a proposition when a reduction is already believed and the extra wires are inferred from path-based inference rules and paths in the network. The set of propositions subconsciously believed by the SNePS agent is the set denoted by the set of nodes that could be gotten by path-based closure of asserted nodes followed by reduction. These nodes are virtually or implicitly in the net, and need be made explicit only when there is a specific reason.