Knowledge, Action, and Ability in the Situation Calculus.

Abstract

The Cognitive Robotics group at the University of Toronto has been studying various aspects of the reasoning and representation problems involving action and change. The setting is that of a (currently simulated) autonomous robot for which we wish to provide high-level control. One problem that has been a central focus of this work is the frame problem [5]. Recently, Reiter, building on the work of Shubert, Haas and Pednault, has proposed a simple solution to this problem in the context of the situation calculus [7]. In the talk, I will briefly review the situation calculus, Reiter's solution to the frame problem, and the regression method he proposes for reasoning about he effect of actions. Effort is now underway to generalize this solution along a number of dimensions. One such generalization concerns knowledge-producing actions, such as sensing, whose effect is to change what is known about he current situation. In [8] it is shown how such actions can be accommodated within the situation calculus. The idea is to introduce an accessibility relation over situations into the language, as was done by Moore [6], and treat alk of knowledge as an abbreviation for talk about accessibility. The relationship between knowledge-producing actions and this accessibility relation then is no different from the relation between other more physical