搜索结果: 16-30 共查到“微分几何学 manifolds”相关记录40条 . 查询时间(0.051 秒)
On $(N(k),ξ)$-semi-Riemannian manifolds: Semisymmetries
(N(k), ξ)-semi-Riemannian manifold T -curvature tensor quasi-conformal curvature tensor
2012/2/29
$(N(k),\xi)$-semi-Riemannian manifolds are defined. Examples and properties of $(N(k),\xi)$-semi-Riemannian manifolds are given. Some relations involving ${\cal T}_{a}$-curvature tensor in $(N(k),\xi)...
Para-CR Structures on almost Paracontact Metric Manifolds
Para-CR manifolds para-Sasakian manifolds almost paracontact metric manifolds paracontact metric manifolds
2012/3/1
Almost paracontact metric manifolds are the famous examples of almost para-CR manifolds. We find necessary and suffcient conditions for such manifolds for be para-CR. Next we examine these conditions ...
On prolongations of contact manifolds
prolongations of contact manifolds Symplectic Geometry Differential Geometry
2011/9/23
Abstract: In this note, we apply spectral sequences to both derive an obstruction to the existence of $n$-fold prolongations and to derive a topological classification. Prolongations were formerly use...
The Intrinsic Geometry of Almost Contact Metric Manifolds
almost contact manifold Sasakian manifold K-contact manifold the intrinsic geometry of almost contact metric manifolds
2011/9/22
Abstract: In this paper the notion of the intrinsic geometry of an almost contact metric manifold is introduced. Description of some classes of spaces with almost contact metric structures in terms of...
Splitting of 3-Manifolds and Rigidity of Area-Minimising Surfaces
Rigidity of Area-Minimising Surfaces Splitting of 3-Manifolds Differential Geometry
2011/9/21
Abstract: In this paper we prove an area comparison result for certain totally geodesic surfaces in 3-manifolds with a lower bound on the scalar curvature. This result is a variant of a comparison the...
Curvature properties of pseudo-sphere bundles over paraquaternionic manifolds
twistor space Einstein manifold paraquaternionic structure mixed 3-structure
2011/9/21
Abstract: In this paper we obtain several curvature properties of the twistor and reflector spaces of a paraquaternionic K\"{a}hler manifold and prove the existence of both positive and negative mixed...
On the curvature of G-manifolds with finitely many non-principal orbits
G-manifold cohomogeneity Ricci curvature
2011/9/20
Abstract: We investigate the curvature of invariant metrics on G-manifolds with finitely many non-principal orbits. We prove existence results for metrics of positive Ricci curvature and non-negative ...
Pseudo-Riemannian Weakly Symmetric Manifolds
Pseudo-Riemannian Weakly Symmetric Manifolds Differential Geometry
2011/9/19
Abstract: There is a well developed theory of weakly symmetric Riemannian manifolds. Here it is shown that several results in the Riemannian case are also valid for weakly symmetric pseudo-Riemannian ...
Geography of symplectic 4- and 6-manifolds
Symplectic geography symplectic sums symplectic structures
2011/9/15
Abstract: The geography of minimal symplectic 4-manifolds with arbitrary fundamental group and symplectic 6-manifolds with abelian fundamental group of small rank, and with arbitrary fundamental group...
Caccioppoli's inequalities on constant mean curvature hypersurfaces in Riemannian manifolds
Caccioppoli’s inequality Simons’ equation constant mean curvature hypersurfaces stable finite index
2011/9/14
Abstract: We prove some Caccioppoli's inequalities for the traceless part of the second fundamental form of a complete, non compact, finite index, constant mean curvature hypersurface of a Riemannian ...
Equidistribution of Eisenstein series on convex co-compact hyperbolic manifolds
Equidistribution of Eisenstein series convex co-compact hyperbolic manifolds Spectral Theory
2011/9/5
Abstract: For convex co-compact hyperbolic manifolds $\Gamma\backslash \mathbb{H}^{n+1}$ for which the dimension of the limit set satisfies $\delta_\Gamma< n/2$, we show that the high-frequency Eisens...
Rigidity of high dimensional graph manifolds
Quasi-isometry quasi-action graph of groups CAT(0) space Borel conjecture Baum-Connes conjecture
2011/9/1
Abstract: We define the class of high dimensional graph manifolds. These are compact smooth manifolds supporting a decomposition into finitely many pieces, each of which is diffeomorphic to the produc...
Thin instantons in G_2-manifolds and Seiberg-Witten invariants
G_2-manifolds and Seiberg-Witten invariants Differential Geometry
2011/9/1
Abstract: For two nearby disjoint coassociative submanifolds C and C' in a G_2-manifold, we construct thin instantons with boundaries lying on C and C' from regular J-holomorphic curves in C. We expla...
On filling minimality of simple Finsler manifolds
simple Finsler manifolds Metric Geometry Differential Geometry
2011/8/30
Abstract: This paper states a formula for the difference of the Holmes-Thompson volumes of two simple Finsler manifolds of arbitrary dimension, in terms of the boundary distances and their derivatives...
Extrinsic hyperspheres in manifolds with special holonomy
Universitat Stuttgart Andrei Moroianu, CMLS
2011/8/30
Abstract: We describe extrinsic hyperspheres and totally geodesic hypersurfaces in manifolds with special holonomy. In particular we prove the nonexistence of extrinsic hyperspheres in quaternion-Kaeh...