"ArtKramr" wrote in message
At this reunion of the 344th Bomb Group I learned of the passing of Bob
Foote,
Arthur Kramer

His son teaches in Bavaria.
Abstract by Prof. Robert L. Foote
Geometry of the Prytz Planimeter
The Prytz planimeter is a simple example of a system governed by a
non-holonomic constraint. It is unique among planimeters in that it measures
something more subtle than area, combining the area, centroid and other
moments of the region being measured. The state space of the planimeter is a
non-principal circle bundle acted on by SL(2,R). The holonomy group is all
of SL(2,R). As a consequence, the planimeter is an example of a system with
a phase shift on the circle that is not a simple rotation.

Erik