Descriptive and prescriptive languages for mobility tasks. Are they different?

We start from the observation that non-trivial mobility tasks can be recognized, described, and performed automatically, based on machine vision. We compare several approaches to representations for tasks at the conceptual level used in this context. All the approaches taken into account have been implemented and used for extensive experiments. It is thus of particular interest to study the relations between descriptive and prescriptive versions of the formulation of a mobility task. In addition, analogies and differences between applications for (indoor) mobile robots and for (outdoor) vision-based automatic road vehicles are compared to better understand the general properties of the required representations.