Summary: Knowledge and Information Systems (2001) 3: 287318
c 2001 Springer-Verlag London Ltd.
Temporal Defeasible Reasoning
Juan C. Augusto and Guillermo R. Simari
Departamento de Cs. de la ComputaciŽon, Universidad Nacional del Sur,
BahŽia Blanca, Argentina
Abstract. An argumentation system that allows temporal reasoning using the notions of
instant and interval is presented. Previous proposals just considered either instants or
intervals. A many-sorted logic is used to represent temporal knowledge at the monotonic
level. The logic considers how to formalize knowledge about explicit temporal references,
events, properties and actions. The argumentation system provides a non-monotonic layer
in which to reason about the justification of truths in the system. The proposal is illustrated
showing how to solve well-known problems of the literature.
Keywords: Defeasible reasoning; Knowledge representation; Temporal reasoning
Argumentation systems (Ches~nevar et al., 1998) are a way to formalize and imple-
ment defeasible reasoning, characterizing the skill that allows us to reason about
a changing world where available information is incomplete or not very reliable.
When new information is available, new reasons to obtain further conclusions
or better reasons to sustain previous conclusions can be considered. But it could