Frame consistency: computing with causal explanations

This paper presents a computational model for reasoning with causal explanations of observations within the framework of Abductive Event Calculus (AEC). The model is based on abductive reasoning based on the notions of ”deserts” and ”oases” on the time line. Our work is motivated from the need to recover from the inconsistency that can arise when observations of fluents are added to the narrative of a domain description. We study how such observations can be assimilated via abductive explanations in order to render the domain frame consistent. Typically, such explanations would involve non-ground events whose time of occurrence can only be constraint within some interval. We present some notions of minimal commitment for such explanations and study how we can reason and compute with these explanations once they have been chosen and added to the theory. The computational model proposed can be readily implemented by exploiting, in a modular way, any of the different computational models for Abductive Logic Programming or for Answer Set Programming, augmented, again in a modular way, by suitable forms of temporal constraint solving.