35 citations · 245 across the 45 of their papers we have counts for
6 papers · 2 filters
Chen Rotational Surfaces of Hyperbolic or Elliptic Type in the Four-dimensional Minkowski Space
Georgi Ganchev, Velichka Milousheva
We study the class of spacelike surfaces in the four-dimensional Minkowski space whose mean curvature vector at any point is a non-zero spacelike vector or timelike vector. These s…
An Invariant Theory of Spacelike Surfaces in the Four-dimensional Minkowski Space
Georgi Ganchev, Velichka Milousheva
We consider spacelike surfaces in the four-dimensional Minkowski space and introduce geometrically an invariant linear map of Weingarten-type in the tangent plane at any point of t…
Schur's theorem of antiholomorphic type for quasi-Kählerian manifolds
Georgi Ganchev, Ognian Kassabov
It is proved, that if a quasi-Kähler manifold of dimension greater or equal to 6 is of pointwise constant antiholomorphic sectional curvature , then , the scalar curvatur…
Nearly Kähler manifolds of constant antiholomorphic sectional curvature
Georgi Ganchev, Ognian Kassabov
A classification theorem for nearly Kähler manifolds of constant antiholomorphic sectional curvature is proved.
Curvature properties and isotropic planes of Riemannian and almost Hermitian manifolds of indefinite metrics
Adrijan Borisov, Georgi Ganchev, Ognian Kassabov
We study two types of isotropic planes: weakly isotropic and strongly isotropic planes. We prove that a Riemannian manifold of indefinite metric is conformally flat if and only if…
Invariants of Lines on Surfaces in
Georgi Ganchev, Velichka Milousheva
Considering the tangent plane at a point to a surface in the four-dimensional Euclidean space, we find an invariant of a pair of two tangents in this plane. If this invariant is ze…