A preliminary reification of argument theory change

Abstract

In this article we introduce the basics for understanding the mechanisms of Argument Theory Change.In particular we reify it using Defeasible Logic Programming. In this formalism, knowledge bases are representedthrough defeasible logic programs. The main change operation we define over a defeasible logic program is aspecial kind of revision that inserts a new argument and then modifies the resulting program seeking for theargument’s warrant. Since the notion of argument refers to a set of defeasible rules, we generalize this techniquein order to handle extended arguments,i.e., arguments containing also strict rules. Hence, revision using extendedarguments allows us to consider program-independent arguments, which brings about new issues. A single notionof minimal change is analyzed, which refers to keep the contents of the program as much as possible. Finally, abrief discussion about the relation between our approach and the basic theory of belief revision is exposed, alongwith a description of other possible (more complex) minimal change principles.