35 citations · 245 across the 45 of their papers we have counts for
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Timelike surfaces with zero mean curvature in Minkowski 4-space
Georgi Ganchev, Velichka Milousheva
On any timelike surface with zero mean curvature in the four-dimensional Minkowski space we introduce special geometric (canonical) parameters and prove that the Gauss curvature an…
On the classification of the almost contact metric manifolds
Valentin A. Alexiev, Georgi T. Ganchev
The vector space of the tensors of type (0,3) having the same symmetries as the covariant derivative of the fundamental form of an almost contact metric manifold is co…
Hermitian Manifolds with Flat Associated Connection
Georgi Ganchev, Ognian Kassabov
A local classification of the Hermitian manifolds with flat associated connection is given. Hermitian manifolds admitting locally a conformal metric with flat associated connection…
An invariant theory of marginally trapped surfaces in the four-dimensional Minkowski space
Georgi Ganchev, Velichka Milousheva
A marginally trapped surface in the four-dimensional Minkowski space is a spacelike surface whose mean curvature vector is lightlike at each point. We associate a geometrically det…
Invariants and bonnet-type theorem for surfaces in $\r^4$
Georgi Ganchev, Velichka Milousheva
In the tangent plane at any point of a surface in the four-dimensional Euclidean space we consider an invariant linear map of Weingarten-type and find a geometrically determined mo…
A Classification of Riemannian manifolds of quasi-constant sectional curvatures
Georgi Ganchev, Vesselka Mihova
Riemannian manifolds of quasi-constant sectional curvatures (QC-manifolds) are divided into two basic classes: with positive or negative horizontal sectional curvatures. We prove t…