t-DeLP: an argumentation-based Temporal Defeasible Logic Programming framework
Publication Type:
Journal ArticleSource:
Annals of Mathematics and Artificial Intelligence, Springer-Verlag (In Press)Keywords:
Temporal Reasoning; Argumentation Systems; Defeasible Logic ProgrammingAbstract:
The aim of this paper is to propose an argumentation-based defeasible logic, called t-DeLP, that focuses on forward temporal reasoning for causal inference. We extend the language of the DeLP logical framework by associating temporal parameters to literals. A temporal logic program is a set of basic temporal facts and (strict or defeasible) durative rules. Facts and rules combine into durative arguments representing temporal processes. As usual, a dialectical procedure determines which arguments are undefeated, and hence which literals are warranted, or defeasibly follow from the program. t-DeLP, though, slightly differs from DeLP in order to accommodate temporal aspects, like the persistence of facts. The output of a t-DeLP program is a set of warranted literals, which is first shown to be non-contradictory and be closed under sub-arguments. This basic framework is then modified to deal with programs whose strict rules encode mutex constraints. The resulting framework is shown to satisfy stronger logical properties like indirect consistency and closure.
Extending a Temporal Defeasible Argumentation Framework with Possibilistic Weights
Publication Type:
Conference PaperSource:
13th European Conference on Logics in Artificial Intelligence (JELIA 2012), p.242-254 (2012)Keywords:
Possibilistic Logic; Temporal Reasoning; Argumentation-based Logic ProgrammingAbstract:
Recently, a temporal extension of the argumentation defea- sible reasoning system DeLP has been proposed. This system, called t-DeLP, allows to reason defeasibly about changes and persistence over time but does not offer the possibility of ranking defeasible rules accord- ing to criteria of preference or certainty (in the sense of belief). In this contribution we extend t-DeLP by allowing to attach uncertainty weights to defeasible temporal rules and hence stratifying the set of defeasible rules in a program. Technically speaking, weights are modelled as neces- sity degrees within the frame of possibility theory, a qualitative model of uncertainty.
