Dynamics of affinely-rigid bodies with degenerate dimension

Dynamical models with degrees of freedom ruled by linear and affine groups have been discussed in various aspects by many people, e.g. O. I. Bogoyavlensky [7] and J. J. Sŀawianowski [4, 5]. We concentrate on models with degenerate dimension, when the configuration space consists of injections from ℝm into ℝn. Equations of motion are derived with special stress on the stationary solutions (stationary ellipses). The isotropic models are related in an interesting way to the theory of Grassmann and stiefel manifolds.