Introduction to the theory of semi-holonomic jets.
We present a generalization of the concept of semiholonomic jets within the framework of higher order prolongations of a fibred manifold. In this respect, a compilation of our 2-fibred manifold approach with the methods of natural operators theory is used.
In this work, we consider variational problems defined by -invariant Lagrangians on the -jet prolongation of a principal bundle , where is the structure group of . These problems can be also considered as defined on the associated bundle of the -th order connections. The correspondence between the Euler-Lagrange equations for these variational problems and conservation laws is discussed.
Let (with ) be vector fields of class in an open set , let be a -dimensional submanifold of and define where is the tangent space to at . Then we expect the following property, which is obvious in the special case when is an interior point (relative to ) of : If is a -density point (relative to ) of then all the iterated Lie brackets of order less or equal to
We study the special Lagrangian Grassmannian , with , and its reduced space, the reduced Lagrangian Grassmannian . The latter is an irreducible symmetric space of rank and is the quotient of the Grassmannian under the action of a cyclic group of isometries of order . The main result of this paper asserts that the symmetric space possesses non-trivial infinitesimal isospectral deformations. Thus we obtain the first example of an irreducible symmetric space of arbitrary rank , which is...