A system, process, and article of manufacture for organizing a large text database into a hierarchy of topics and for maintaining this organization as documents are added and deleted and as the topic hierarchy changes. Given sample documents belonging to various nodes in the topic hierarchy, the tokens...http://www.google.com/patents/US20010037324?utm_source=gb-gplus-sharePatent US20010037324 - Multilevel taxonomy based on features derived from training documents classification using fisher values as discrimination values
