http://www.w3.org/2000/10/swap/cwm.py Closed World Machine (also, in Wales, a valley - topologiclly a partially closed world perhaps?) This is an application which knows a certian amount of stuff and can manipulate it. It uses llyn, a (forward chaining) query engine, not an (backward chaining) inference engine: that is, it will apply all rules it can but won't figure out which ones to apply to prove something.