A class of boundary problems for extremal surfaces of mixed type in Minkowski 3-space.
We provide the tangent bundle of pseudo-Riemannian manifold with the Sasaki metric and the neutral metric . First we show that the holonomy group of contains the one of . What allows us to show that if is indecomposable reducible, then the basis manifold is also indecomposable-reducible. We determine completely the holonomy group of according to the one of . Secondly we found conditions on the base manifold under which ( respectively ) is Kählerian, locally symmetric or Einstein...
A classification theorem is obtained for submanifolds with parallel second fundamental form of an 𝑆-manifold whose invariant f-sectional curvature is constant.
The aim of this paper is to classify (lócally) all torsion-less locally homogeneous affine connections on two-dimensional manifolds from a group-theoretical point of view. For this purpose, we are using the classification of all non-equivalent transitive Lie algebras of vector fields in ℝ2 according to P.J. Olver [7].
Let G be a complex reductive connected algebraic group equipped with the Sklyanin bracket. A classification of Poisson homogeneous G-spaces with connected isotropy subgroups is given. This result is based on Drinfeld's correspondence between Poisson homogeneous G-spaces and Lagrangian subalgebras in the double D𝖌 (here 𝖌 = Lie G). A geometric interpretation of some Poisson homogeneous G-spaces is also proposed.