Goal change in the situation calculus

Although there has been much discussion of belief change (e.g. [4, 21]), goal change has not received much attention. In this paper, we propose a method for goal change in the framework of Reiters; [12] theory of action in the situation calculus [8, 10], and investigate its properties. We extend the framework developed by Shapiro et al. [17] and Shapiro and Lesprance [16], where goals and goal expansion were modelled, but goal contraction was not.