An incremental approach to structured argumentation over dynamic knowledge bases

Considering the structure of arguments allows users to analyze reasons for and against a conclusion; the warrant status of such a conclusion in the context of a knowledge base represents the main output of a dialectical process. A naive approach to computing such statuses is costly, and any update to the knowledge base potentially has a huge impact if done in this manner. We study the case of updates consisting of both additions and removals of pieces of knowledge in the Defeasible Logic Programming (DeLP) framework, first analyzing the complexity of the problem and then identifying conditions under which we can avoid unnecessary computations—central to this is the development of data structures to keep track of which results can potentially be affected by a given update. We also present experiments showing that our incremental algorithm yields significantly lower running times in practice, as well as overall fewer recomputations.