共查询到19条相似文献,搜索用时 93 毫秒
1.
The authors obtain various versions of the Omori-Yau's maximum principle on complete properly immersed submanifolds with controlled mean curvature in certain product manifolds,in complete Riemannian manifolds whose k-Ricci curvature has strong quadratic decay,and also obtain a maximum principle for mean curvature flow of complete manifolds with bounded mean curvature.Using the generalized maximum principle,an estimate on the mean curvature of properly immersed submanifolds with bounded projection in N1 in the product manifold N1 ×N2 is given.Other applications of the generalized maximum principle are also given. 相似文献
2.
邱红兵 《数学物理学报(B辑英文版)》2013,33(6):1561-1570
We obtain the Omori-Yau maximum principle on complete properly immersed submanifolds with the mean curvature satisfying certain condition in complete Riemannian manifolds whose radial sectional curvature satisfies some decay condition, which generalizes our previous results in [17]. Using this generalized maximum principle, we give an estimate on the mean curvature of properly immersed submanifolds in H^n × R^e with the image under the projection on H^n contained in a horoball and the corresponding situation in hyperbolic space. We also give other applications of the generalized maximum principle. 相似文献
3.
Warped product manifolds are known to have applications in physics. For instance, they provide an excellent setting to model space-time near a black hole or a massive star (cf. [9]). The studies on warped product manifolds with extrinsic geometric point of view were intensified after the B.Y. Chen's work on CR-warped product submanifolds of Kaehler manifolds (cf. [6], [7]). Later on, similar studies were carried out in the setting of 1.c.K. manifolds and nearly Kaehler manifolds (el. [3], [11]). In the present article, we investigate a larger class of warped product submanifolds of 1.c.K. manifolds, ensure their existence by constructing an example of such manifolds and obtain some important properties of these submanifolds. With regard to the CR-warped product submanifold, a special case of generic warped product submanifolds, we obtain a characterization under which a CR-submanifold is reducesd to a CR-warped product submanifold. 相似文献
4.
A well-known result for Vilenkin systems is the fact that for all 1 p ∞ the n-th partial sums of Fourier series of all functions in the space Lpconverge to the function in Lp-norm.This statement can not be generalized to any representative product system on the complete product of finite non-abelian groups,but even then it is true for the complete product of quaternion groups with bounded orders and monomial representative product system ordered in a specific way. 相似文献
5.
Xiangzhi CAO 《数学年刊B辑(英文版)》2017,38(5):1071-1076
This paper deals with the p-harmonic function on a complete non-compact submanifold M isometrically immersed in an (n + k)-dimensional complete Riemannian manifold (M) of non-negative (n-1)-th Ricci curvature.The Liouville type theorem about the p-harmonic map with finite Lq-energy from complete submanifold in a partially nonnegatively curved manifold to non-positively curved manifold is also obtained. 相似文献
6.
朱琳 《高等学校计算数学学报》2021,(1):83-96
Based on the maximum principle,the difference formula defined on a non-integral node is given to approximate the fractional Riemann-Liouville derivative and the finite difference scheme for solving one-dimensional space fractional diffusion equations(FDEs) with variable coefficients is presented.Furthermore,using the maximum principle the scheme is proved unconditionally stable and secondorder accuracy in spatial grid size.Several numerical examples are given to verify the efficiency of the scheme. 相似文献
7.
This paper is concerned with Bernstein polynomials on k-simploids by which we mean a crossproduct of k lower dimensional simplices. Specifically, we show that if the Bernstein polynomials ofa given function f on a k-simploid form a decreasing sequence then f+l, where l is any correspondingtensor product of affine functions. achieves its maximum on the boundary of the k-simploid. Thisextends recent results in [1] for bivariate Bernstein polynomials on triangles. Unlike the approachused in [1] our approach is based on semigroup techniques and the maximum principle for secondorder elliptic operators. Furthermore, we derive analogous results for cube spline surfaces. 相似文献
8.
Let(M~n, g)(n ≥ 3) be an n-dimensional complete Riemannian manifold with harmonic curvature and positive Yamabe constant. Denote by R and R?m the scalar curvature and the trace-free Riemannian curvature tensor of M, respectively. The main result of this paper states that R?m goes to zero uniformly at infinity if for p ≥ n, the L~p-norm of R?m is finite.As applications, we prove that(M~n, g) is compact if the L~p-norm of R?m is finite and R is positive, and(M~n, g) is scalar flat if(M~n, g) is a complete noncompact manifold with nonnegative scalar curvature and finite L~p-norm of R?m. We prove that(M~n, g) is isometric to a spherical space form if for p ≥n/2, the L~p-norm of R?m is sufficiently small and R is positive.In particular, we prove that(M~n, g) is isometric to a spherical space form if for p ≥ n, R is positive and the L~p-norm of R?m is pinched in [0, C), where C is an explicit positive constant depending only on n, p, R and the Yamabe constant. 相似文献
9.
李洪波 《数学物理学报(B辑英文版)》2009,29(4):991-1004
In an inner-product space, an invertible vector generates a reflection with respect to a hyperplane, and the Clifford product of several invertible vectors, called a versor in Clifford algebra, generates the composition of the corresponding reflections, which is an orthogonal transformation. Given a versor in a Clifford algebra, finding another sequence of invertible vectors of strictly shorter length but whose Clifford product still equals the input versor, is called versor compression. Geometrically, versor compression is equivalent to decomposing an orthogonal transformation into a shorter sequence of reflections. This paper proposes a simple algorithm of compressing versors of symbolic form in Clifford algebra. The algorithm is based on computing the intersections of lines with planes in the corresponding Grassmann-Cayley algebra, and is complete in the case of Euclidean or Minkowski inner-product space. 相似文献
10.
A stochastic maximum principle for the risk-sensitive optimal control problem of jump diffusion processes with an exponential-of-integral cost functional is derived assuming that the value function is smooth, where the diffusion and jump term may both depend on the control. The form of the maximum principle is similar to its risk-neutral counterpart. But the adjoint equations and the maximum condition heavily depend on the risk-sensitive parameter. As applications, a linear-quadratic risk-sensitive control problem is solved by using the maximum principle derived and explicit optimal control is obtained. 相似文献
11.
设S~(n+p)(1)是一单位球面,M~n是浸入S~(n+p)(1)的具有非零平行平均曲率向量的n维紧致子流形.证明了当n≥4,p≥2时,如果M~n的Ricci曲率不小于(n-2)(1+H~2),则M~n是全脐的或者M~n的Ricci曲率等于(n-2)(1+H~2),进而M~n的几何分类被完全给出. 相似文献
12.
本文的主要建立非齐性度量测度空间上双线性强奇异积分算子$\widetilde{T}$及交换子$\widetilde{T}_{b_{1},b_{2}}$在广义Morrey空间$M^{u}_{p}(\mu)$上的有界性. 在假设Lebesgue可测函数$u, u_{1}, u_{2}\in\mathbb{W}_{\tau}$, $u_{1}u_{2}=u$,且$\tau\in(0,2)$. 证明了算子$\widetilde{T}$是从乘积空间$M^{u_{1}}_{p_{1}}(\mu)\times M^{u_{2}}_{p_{2}}(\mu)$到空间$M^{u}_{p}(\mu)$有界的, 也是从乘积空间$M^{u_{1}}_{p_{1}}(\mu)\times M^{u_{2}}_{p_{2}}(\mu)$到广义弱Morrey空间$WM^{u}_{p}(\mu)$有界的,其中$\frac{1}{p}=\frac{1}{p_{1}}+\frac{1}{p_{2}}$及$1相似文献
13.
A small cover is a closed manifold $M^{n}$ with a locally standard
$(\Bbb{Z}_{2})^{n}$-action such that its orbit space is a simple
convex polytope $P^{n}$. Let $\Delta^{n}$ denote an $n$-simplex and
$P(m)$ an $m$-gon. This paper gives formulas for calculating the
number of D-J equivalent classes and equivariant homeomorphism
classes of orientable small covers over the product space
$\Delta^{n_1}\times \Delta^{n_2} \times P(m)$, where $n_1$ is odd. 相似文献
14.
Let $M^{3}$ be a 3-dimensional paracontact metric manifold. Firstly, a classification of $M^{3}$ satisfying $\varphi Q=Q\varphi$ is given. Secondly, manifold $M^{3}$ satisfying $\varphi l=l\varphi$ and having $\eta$-parallel Ricci tensor or cyclic $\eta$-parallel Ricci tensor is studied. 相似文献
15.
Let $M^{n}(n\geq4)$ be an oriented compact submanifold with parallel
mean curvature in an $(n+p)$-dimensional complete simply connected
Riemannian manifold $N^{n+p}$. Then there exists a constant
$\delta(n,p)\in(0,1)$ such that if the sectional curvature of $N$
satisfies $\ov{K}_{N}\in[\delta(n,p), 1]$, and if $M$ has a lower
bound for Ricci curvature and an upper bound for scalar curvature,
then $N$ is isometric to $S^{n+p}$. Moreover, $M$ is either a
totally umbilic sphere $S^n\big(\frac{1}{\sqrt{1+H^2}}\big)$, a
Clifford hypersurface
$S^{m}\big(\frac{1}{\sqrt{2(1+H^2)}}\big)\times
S^{m}\big(\frac{1}{\sqrt{2(1+H^2)}}\big)$ in the totally umbilic
sphere $S^{n+1}\big(\frac{1}{\sqrt{1+H^2}}\big)$ with $n=2m$, or
$\mathbb{C}P^{2}\big(\frac{4}{3}(1+H^2)\big)$ in
$S^7\big(\frac{1}{\sqrt{1+H^2}}\big)$. This is a generalization of
Ejiri''s rigidity theorem. 相似文献
16.
This paper gives some sufficient conditions for a compact Kaehler submanifold M~n in a locally symmetric Bochner-Kaehler manifold ~(n p) to be totally geodesic. The conditions are given by inequalities which are established between. the sectional curvature(resp, holomorphic sectional curvature) of M~n and the Ricci curvature of ~(n p). In particular, similar results in the case where ~(n p) is a complex projective spathe are contained. 相似文献
17.
The aim of this paper is to establish the necessary and sufficient conditions for the compactness of fractional integral commutator[b,Iγ]which is generated by fractional integral Iγand function b∈Lipβ(μ)on Morrey space over non-homogeneous metric measure space,which satisfies the geometrically doubling and upper doubling conditions in the sense of Hytonen.Under assumption that the dominating functionλsatisfies weak reverse doubling condition,the author proves that the commutator[b,Iγ]is compact from Morrey space Mqp(μ)into Morrey space Mts(μ)if and only if b∈Lipβ(μ). 相似文献
18.
Mihaly Kovacs 《Semigroup Forum》2005,71(3):462-470
For a generator $A$ of a $C_0$-semigroup $T(\cdot)$ on a Banach space $X$ we consider the semi-norm $M^{k}_x:=\limsup_{t\to
0+}\|t^{-1}(T(t)-I)A^{k-1}x\|$ on the Favard space ${\cal F}_{k}$ of order $k$ associated with $A$. The use of this semi-norm
is motivated by the functional analytic treatment of time-discretization methods of linear evolution equations. We show that
sharp inequalities for bounded linear operators on ${\cal D}(A^k)$ can be extended to the larger space ${\cal F}_{k}$ by using
the semi-norm $M^{k}_{(\cdot)}$. We also show that $M^{k}_{(\cdot)}$ is a norm equivalent to the norms that are usually considered
in the literature if A has a bounded inverse. 相似文献
19.
Henrique F. de Lima Marco A. L. Velásquez 《Bulletin of the Brazilian Mathematical Society》2013,44(1):49-65
Our purpose is to study the geometry of linear Weingarten spacelike hypersurfaces immersed in the de Sitter space $\mathbb{S}_1^{n + 1} $ . In this setting, by using as main analytical tool a suitable maximum principle for complete noncompact Riemannian manifolds, we establish new characterizations of the hyperbolic cylinders of $\mathbb{S}_1^{n + 1} $ . In the compact case, we obtain a rigidity result concerning to a such hypersurface according to the length of its second fundamental form. 相似文献