Handling Exceptions in nonmonotonic reasoning

Abstract We introduce some differences in the style defeasible information is represented and inferences are made in nonmonotonic reasoning. These, at first sight harmless, changes, in fact, helped us to discover a very important principle guiding how inferences should be drawn in nonmonotonic reasoning, we name it the exception-first principle or EFP. DLEF is our own variant for default logic complying with EFP. We also show alternative definitions for Reiter’s default logics and its justified and constrained variants within our framework. DLEF does not produce anomalous extensions where the other default logics do. Restricted to the language of general logic programs, DLEF, Reiter’s default logic and answer set programming all coincide. This explains why ASP is appointed as a solution to the anomalous extensions problem, ASP complies with EFP.

• Type: Conference
• Year: 2007
• Where: LANMR
• Authors: Marcelino C. Pequeno, Rodrigo de M. S. Veras, Wladimir A. Tavares
• Keywords: Default Logic, LANMR 2007, Logical Reasoning, Nonmonotonic Reasoning, Reiter’s Default Logic