A uniform representation for time and space and their mutual constraints

AbstractMuch recent work in reasoning systems has concentrated on the role of time in planning, action modeling, and tasks in domains where time is important. On the other hand, there are systems that concentrate on spatial reasoning, especially where manipulation or managing of the environment is important, as in robot route planning. The integration of the two themes is a goal which, if possible, would allow the interaction of space and time to be explored. A problem-solving system would then be able to reason about the times at which actions might occur, in the light of spatial constraints, or vice versa, to reason about the places in which actions take place, and the temporal constraints involved. This paper shows a way to integrate the representation of both time and space in a framework that allows uniform reasoning across both dimensions. An ontology for objects, events, states, and processes is provided using conceptual graphs for representation, and a syntactic extension to Sowa's conceptual graph formalism (see Sowa's article, this volume) is presented to support the effort