Representing Continuous Change in the Event Calculus

Murray Shanahan


The Event Calculus of Kowalski and Sergot only deals with discrete change. This paper introduces a simplified version of the Event Calculus and extends it to deal with continuous change, as in the height of a falling object or the level of liquid in a filling vessel. The idea of autotermination is introduced. A period of continuous change autoterminates if it brings about the event which terminates it. For example, when the increasing level of water in a sink reaches the overflow, it ceases to increase. The formulation is applied to a simple example with liquid filling a sink, and to a more complicated one with many tanks discharging liquid into another tank.