搜索结果: 46-60 共查到“知识库 微分几何学”相关记录252条 . 查询时间(4.898 秒)
Collapsing 4-manifolds under a lower curvature bound
collapsing Gromov-Hausdorff convergence Alexandrov spaces topology of 4-manifolds
2012/5/24
In this paper we describe the topology of 4-dimensional closed orientable Riemannian manifolds with a uniform lower bound of sectional curvature and with a uniform upper bound of diameter which collap...
An index formula for simple graphs
Curvature topological invariants graph theory Euler characteristic
2012/5/24
Gauss-Bonnet for simple graphs G assures that the sum of curvatures K(x) over the vertex set V of G is the Euler characteristic X(G). Poincare-Hopf tells that for any injective function f on V the sum...
Variation of Hodge structure for generalized complex manifolds
Variation of Hodge structure generalized complex manifolds Differential Geometry
2012/5/9
A generalized complex manifold which satisfies the $\partial \overline{\partial}$-lemma admits a Hodge decomposition in twisted cohomology. Using a Courant algebroid theoretic approach we study the be...
Some properties of Holder surfaces in the Heisenberg group
properties of Holder surfaces Heisenberg group Differential Geometry
2012/5/9
It is a folk conjecture that for alpha > 1/2 there is no alpha-Hoelder surface in the subRiemannian Heisenberg group. Namely, it is expected that there is no embedding from an open subset of R^2 into ...
Dyck's surfaces, systoles, and capacities
Systole optimal systolic inequality extremal metric nonpositively curved surface Riemann surface
2012/5/9
We prove an optimal systolic inequality for nonpositively curved Dyck's surfaces. The extremal surface is flat with eight conical singularities, six of angle theta and two of angle 9?pi - theta, for a...
A Tale of Two Arc Lengths: Metric notions for curves in surfaces in equiaffine space
anne curve anne arc length anne surface anne first fundamental form
2012/5/9
In Euclidean geometry, all metric notions (arc length for curves, the first fundamental form for surfaces, etc.) are derived from the Euclidean inner product on tangent vectors, and this inner product...
Non-Null Weakened Mannheim curves
Mannheim Cuves Frenet-Mannheim Curves Weakened-Mannheim Curves
2012/4/16
In this study, non-null Frenet-Mannheim curves and non-null Weakened Mannheim curves are investigated in Minkowski 3-space. Some characterizations for this curves are obtained.
Adapted connections on metric contact manifolds
Adapted connections metric contact manifolds Differential Geometry
2012/4/16
In this paper, we describe the space of adapted connections on a metric contact manifold through the space of their torsion tensors. The torsion tensor is an element of the space of TM-valued two-form...
Spherical Indicatrices of Involute of a Space Curve in Euclidean 3-Space
Involute curve Evolute curve Helix, Slant helix Spherical indicatrix
2012/4/16
In this work, we studied the properties of the spherical indicatrices of involute curve of a space curve and presented some characteristic properties in the cases that involute curve and evolute curve...
On the existence of nilsolitons on 2-step nilpotent Lie groups
existence nilsolitons 2-step nilpotent Lie groups Differential Geometry
2012/4/16
A 2-step nilpotent Lie algebra n is said to be of type (p,q)if dim(n)=p+q and dim([n,n])=p. By considering a class of 2-step nilpotent Lie algebras naturally attached to graphs, we prove that there ex...
Mean curvature flows and isotopy problems
Mean curvature flows isotopy problems Differential Geometry
2012/4/23
In this note, we discuss the mean curvature flow of graphs of maps between Riemannian manifolds. Special emphasis will be placed on estimates of the flow as a non-linear parabolic system of differenti...
Information geometry and the hydrodynamical formulation of quantum mechanics
Information geometry the hydrodynamical formulation quantum mechanics Differential Geometry
2012/4/18
Let (M,g) be a compact, connected and oriented Riemannian manifold. We denote D the space of smooth probability density functions on M.
Integral geometry of complex space forms
Integral geometry complex space forms Differential Geometry
2012/4/18
Using the language of Alesker's theory of valuations on manifolds, a thorough account of the integral geometry of the complex space forms is given. The local kinematic formulas on complex space forms ...
We work in both the complex and in the para-complex categories and examine (para)-K\"ahler Weyl structures in both the geometric and in the algebraic settings. The higher dimensional setting is quite ...
Fenchel-Nielsen Coordinates for Maximal Representations
Fenchel-Nielsen Coordinates Maximal Representations
2012/4/23
We develop Fenchel-Nielsen coordinates for representations of surface groups into Sp(2n,R) with maximal Toledo invariant. Analogous to classical Fenchel-Nielsen coordinates on the Teichm\"uller space ...