SNePS
SNePS (Semantic Network Processing System) is an AI system for building, using and retrieving information from propositional semantic networks. It includes an inference package (SNIP), a belief revision system (SNeBR), a natural language processing system (SNaLPS), a command language (SNePSUL), and a graphical editing and display environment for semantic networks (XGinseng).

The project page provides the source code, which is distributed under the terms of the GPL. SNePS is known to run on a number of Lisp implementations including CLISP and CMUCL. Its GUI is based on Garnet.


Knowledge Representation Systems