4-Dimensional (Para)-Kähler-Weyl Structures
We investigate ∇-flat and pointwise-∇-flat functions on affine and Riemannian manifolds. We show that the set of all ∇-flat functions on (M,∇) is a ring which has interesting properties similar to the ring of polynomial functions.
In this paper we study vector fields in Riemannian spaces, which satisfy , , We investigate the properties of these fields and the conditions of their coexistence with concircular vector fields. It is shown that in Riemannian spaces, noncollinear concircular and -vector fields cannot exist simultaneously. It was found that Riemannian spaces with -vector fields of constant length have constant scalar curvature. The conditions for the existence of -vector fields in symmetric spaces are given....