Some characterizations of special curves in the Euclidean space .
The object of the present paper is to study a quarter-symmetric metric connection in an Lorentzian -Sasakian manifold. We study some curvature properties of an Lorentzian -Sasakian manifold with respect to the quarter-symmetric metric connection. We study locally -symmetric, -symmetric, locally projective -symmetric, -projectively flat Lorentzian -Sasakian manifold with respect to the quarter-symmetric metric connection.
We show that asserting the regularity (in the sense of Rund) of a first-order parametric multiple-integral variational problem is equivalent to asserting that the differential of the projection of its Hilbert-Carathéodory form is multisymplectic, and is also equivalent to asserting that Dedecker extremals of the latter -form are holonomic.
In this paper some properties of an immersion of two-dimensional surface with boundary into are studied. The main tool is the maximal principle property of a solution of the elliptic system of partial differential equations. Some conditions for a surface to be a part of a 2-dimensional spheren in are presented.
In this paper, we characterize a class of biharmonic maps from and between product manifolds in terms of the warping function. Examples are constructed when one of the factors is either Euclidean space or sphere.
We consider the set of all almost Kähler structures (g,J) on a 2n-dimensional compact orientable manifold M and study a critical point of the functional with respect to the scalar curvature τ and the *-scalar curvature τ*. We show that an almost Kähler structure (J,g) is a critical point of if and only if (J,g) is a Kähler structure on M.
In this paper, we consider some evolution equations of generalized Ricci curvature and generalized scalar curvature under the List’s flow. As applications, we obtain -estimates for generalized scalar curvature and the first variational formulae for non-negative eigenvalues with respect to the Laplacian.
We produce new examples of harmonic maps, having as source manifold a space of constant curvature and as target manifold its tangent bundle , equipped with a suitable Riemannian -natural metric. In particular, we determine a family of Riemannian -natural metrics on , with respect to which all conformal gradient vector fields define harmonic maps from into .