Andrei A. Agrachev

SISSA and Steklov Math. Inst.

On the Curvature of Control Systems

The curvature tensor on a Riemannian manifold reflects intrinsic properties of the geodesic flow, i.e. the properties which do not depend on the choice of local coordinates. In particular, nonzero curvature is an obstruction for the simultaneous rectification of the geodesics by a change of coordinates.

The knowledge of the curvature gives a fundamental information about the behavior of geodesics and about the structure of optimal synthesis. On the other hand, in order to evaluate the curvature we don't need to solve the geodesics differential equation, it is enough to compute certain polynomials of the partial derivatives of its right-hand side.

Riemannian geodesics are just extremals of a special optimization problem, the problem to find a shortest path between to points on the manifold. Why not to try to find analogues of the curvature for general optimal control problems? This talk is an attempt of a light presentation of the large program going in that direction.


Abstract in Postscript


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