MODIFYING INTENSIONAL LOGIC KNOWLEDGE

This paper addresses the problem of updating knowledge encoded in the form of a logic program. Our approach is based upon the idea of executing a basic update by directly modifying the truth valuation of the (intensionally or extensionally defined) atom which is the object of an update. The modifications propagate, in a recursive fashion, to the truth valuations of atoms depending on the updated one. An update language is defined around this central idea. The language is built upon two basic update operators, respectively denoting insertion and deletion of a positive literal (atom). Several structures are defined for combining basic updates into complex ones and controlling the execution flow.