We generalize the concept of a Jacobi field to nonholonomic Riemannian geometry, considering both fields, and, more generally, restricted fields. In first case, corresponding equation involves connection and Schouten curvature tensor. second connections tensors arising in construction Wagner also briefly discuss existence

We introduce a two-dimensional sigma model associated with Jacobi manifold. The is generalisation of Poisson providing topological open string theory. In the Hamiltonian approach first class constraints are derived, which generate gauge invariance under diffeomorphisms. reduced phase space finite-dimensional. By introducing metric tensor on target, non-topological obtained, yielding Polyakov ac...

In this paper the number of Fq-isomorphism classes of Jacobi quartic curves, i.e., the number of Jacobi quartic curves with distinct jinvariants, over finite field Fq is enumerated.