搜索结果: 1-15 共查到“数学 flat”相关记录37条 . 查询时间(0.057 秒)
We introduce the notion of recurrent geodesic rays in
a complete °at Lorentz 3-manifold. We completely classify the
dynamical behavior of geodesics in cyclic quotients, and apply this
classiˉcation...
THE FUNDAMENTAL GROUP OF A COMPACT FLAT LORENTZ SPACE FORM IS VIRTUALLY POLYCYCLIC
lorentz Multi-loop spatial form
2015/9/29
A flat Lorentz space form is a geodesically complete Lorentzian manifold of
zero curvature. It is well known (see Auslander & Markus [3]) that such a space
M may be represented as a quotient Rw
/Γ,...
Let G be a solvable linear Lie group. We show that for every flat
pnncipal G-bundle { over a CW-complex M, there is a finite-sheeted covering
spacep: M-3 M such that p*C is trivial as a principal ...
ON LOCALLY CONFORMALLY FLAT GRADIENT SHRINKING RICCI SOLITONS
SHRINKING RICCI SOLITONS CONFORMALLY FLAT
2015/8/17
In this paper, we first apply an integral identity on Ricci solitons to prove that
closed locally conformally flat gradient Ricci solitons are of constant sectional curvature.
We then ge...
Convergence of scalar-flat metrics on manifolds with boundary under the Yamabe flow
Convergence of scalar-flat metrics manifolds boundary under the Yamabe flow Differential Geometry
2012/6/21
This paper is concerned with a Yamabe-type flow for compact Riemannian manifolds with boundary. The convergence of this flow is established if the manifold with boundary satisfies either a generic con...
Frobenius 3-folds via singular flat 3-webs
Frobenius 3-folds singular flat 3-webs Differential Geometry
2012/6/15
We give a geometric interpretation of weighted homogeneous solutions to the associativity equation in terms of the web theory and construct a massive Frobenius 3-fold germ via a singular 3-web germ sa...
Bach-flat gradient steady Ricci solitons
Bach-flat gradient Ricci solitons Differential Geometry
2011/9/19
Abstract: In this paper we prove that any $n$-dimensional ($n\ge 4$) complete Bach-flat gradient steady Ricci solitons with positive Ricci curvature is isometric to the Bryant soliton. We also show th...
Numerical ranges of companion matrices: flat portions on the boundary
numerical range companion matrix Functional Analysis Algebraic Geometry
2011/9/9
Abstract: Criterion for a companion matrix to have a certain number of flat portions on the boundary of its numerical range is given. The criterion is specialized to the cases of 3-by-3 and 4-by-4 mat...
Mass-capacity inequalities for conformally flat manifolds with boundary
Mass-capacity inequalities conformally flat manifolds boundary
2011/8/29
Abstract: In this paper we prove a mass-capacity inequality and a volumetric Penrose inequality for conformally flat manifolds, in arbitrary dimensions. As a by-product of the proofs, capacity and Ale...
Rings over which every module has a flat $δ$-cover
-covers -perfect rings -semiperfect rings Flat modules
2011/8/25
Abstract: Let $M$ be a module. A {\em $\delta$-cover} of $M$ is an epimorphism from a module $F$ onto $M$ with a $\delta$-small kernel. A $\delta$-cover is said to be a {\em flat $\delta$-cover} in ca...
Hypersurfaces in non-flat Lorentzian space forms satisfying $L_k\psi=A\psi+b$
linearized operator Lk isoparametric hypersurface k-maximal hypersurface
2011/1/21
We study hypersurfaces either in the De Sitter space Sn+1 1 ⊂ Rn+2 1 or in the anti De
Sitter space Hn+1 1 ⊂ Rn+2 2 whose position vector satisfies the condition Lk = A + b,
This paper deals with well-known notion of PF-rings, that is, rings in which principal ideals are flat. We give a new characterization of PF-rings. Also, we provide a necessary and sufficient conditio...
Non-existence of CR submanifolds of maximal CR dimension satisfying RA = 0 in non-flat complex space forms
Complex space form CR submanifold of maximal CR dimension
2011/2/25
It has been proved that there are no real hypersurfaces satisfying RA =0 in non-flat complex space forms. In this paper we prove that the same is true in the case of CR submanifolds of maximal CR dime...
Uniqueness of the Foliation of Constant Mean Curvature Spheres in Asymptotically Flat 3-Manifolds
Uniqueness Foliation of Constant Mean Curvature Spheres Asymptotically Flat 3-Manifolds
2011/2/21
In this paper I study the constant mean curvature surface in asymp-totically flat 3-manifolds with general asymptotics. Under some weak condition, I prove that outside some compact set in the asymptot...
Let R be a noetherian commutative ring, and F : · · · → F2 → F1 → F0 → 0 a complex of flat R-modules. We prove that if (p) ⊗R F is acyclic for every p ∈ SpecR, then F is acyclic, and H0(F) is R...