共查询到20条相似文献,搜索用时 62 毫秒
1.
通过构造辅助函数,利用基本对称函数的性质以及函数在极大值点的性质,得到Hessian型方程S_k(D~2u-A(x,u,Du))=B(x,u)的梯度内估计,构造不同的辅助函数,分近边、边界和内部3种情形讨论该方程Neumann边值问题,进而得到全局梯度估计. 相似文献
2.
研究了含梯度项的椭圆方程组的边界爆破解的性质,其中权函数a(x),b(x)为正并且满足一定的条件.利用上下解的方法及比较原则证明了正解的存在性与唯一性,并得到了边界爆破速率的估计. 相似文献
3.
In this paper,we study gradient estimates for the nonlinear heat equation ut-△u =au log u,on compact Riemannian manifold with or without boundary.We get a Hamilton type gradient estimate for the positi... 相似文献
4.
文中得到半线性椭圆型方程的爆破问题解的存在性,其中或者是Rn中的有界区域,C3,C4,C5,C6是正常数,并且C5,C3(0,1). 相似文献
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该文致力于研究如下Monge-Ampère方程边界爆破解的最优估计和严格凸解的不存在性M[u](x)=K(x)f(u),x∈Ω,u(x)→+∞当dist(x,?Ω)→0.这里M[u]=det(uxixj)是Monge-Ampère算子,Ω是RN(N≥2)中的光滑有界严格凸区域.文中不仅得到了K(x)和f(u)的各种条件之间的关系,还通过和已有文献中相关结果的比较明确了条件和估计之间的关系.并且,在Ω是一般区域的情况下给出了严格凸解不存在的结果,而这在以往文献中尚未提及. 相似文献
7.
在区域Ω的边界满足一致p厚条件下,利用一致p厚的边界Sobolev不等式、一些容量不等式和一个精确的逆Hlder不等式,我们给出了一类拟线性椭圆型方程divAp(x,Du) Bp(x,u,Du)=f(x)弱解梯度的一致估计. 相似文献
8.
本文对p-Laplace Schr(o|¨)dinger热方程正连续弱解做了椭圆型梯度估计;作为应用,本文得到了一个关于p-Laplace算子的Liouville型结果;并证明了关于p-LaplaceSchr(o|¨)dinger热方程正连续弱解的Harnack不等式. 相似文献
9.
In this paper,the 16-parameter nonconforming tetrahedral element which has an energy-orthogonal shape function space is presented for the discretization of fourth order elliptic partial differential operators in three spatial dimensions.The newly constructed element is proved to be convergent for a model biharmonic equation. 相似文献
10.
本文研究方程带两参数的高阶椭圆型方程一般边值问题解的渐近式的构造.用两参数表示法给出渐近解的表达式和有关的余项估计.拓广了文[1]和[7]的结果. 相似文献
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The elliptic differential equations of second order \sum^n_{i,j=1}D_i[A_{ij}(x, y)D_jy] + P(x, y) + Q(x, y, ∇y) = e(x), x ∈ Ω . will be considered in an exterior domain Ω⊂ R^n, n ≥ 2. Some oscillation criteria are given by integral averaging technique. 相似文献
13.
We study boundary blow-up solutions of semilinear elliptic equations Lu = u + p with p > 1, or Lu = e au with a > 0, where L is a second order elliptic operator with measurable coefficients. Several uniqueness theorems and an existence theorem are obtained. 相似文献
14.
Gaussian Curvature Estimates for the Convex Level Sets of Solutions for Some Nonlinear Elliptic Partial Differential Equations
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Peihe Wang & Wei Zhang 《偏微分方程(英文版)》2012,25(3):239-275
We give lower bound estimates for the Gaussian curvature of convex level sets of minimal surfaces and the solutions to semilinear elliptic equations in terms of the norm of boundary gradient and the Gaussian curvature of the boundary. 相似文献
15.
Bian Baojun 《偏微分方程(英文版)》1991,4(1)
We consider the problem of existence for viscosity solutions of seoond order fully nonlinear elliptic partial differential equations F(D²u, Du, u, z) = 0. We prove existence results for viscosity solutions in W^{1,∞} under assumptions that function F satisfies the natural structure conditions. We do not assume F is convex. 相似文献
16.
We study the numerical approximation of boundary optimal control problems governed by semilinear elliptic partial differential equations with pointwise constraints on the control. The analysis of the approximate control problems is carried out. The uniform convergence of discretized controls to optimal controls is proven under natural assumptions by taking piecewise constant controls. Finally, error estimates are established and some numerical experiments, which confirm the theoretical results, are performed.The first two authors were supported by Ministerio de Ciencia y Tecnología (Spain). The second author was also supported by the DFG research center “Mathematics for key technologies” (FZT86) in Berlin. 相似文献
17.
Second Order Estimates for Non-Concave Hessian Type Elliptic Equations on Riemannian Manifolds
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Heming Jiao 《数学研究》2015,48(3):275-289
In this paper, we derive second order estimates for a class of non-concave
Hessian type elliptic equations on Riemannian manifolds. By applying a new method
for $C^2$ estimates, we can weaken some conditions, which works for some non-concave
equations. Gradient estimates are also obtained. 相似文献
18.
本文讨论了球上半线性椭圆Dirichlet问题Δu+λuq+up=0正解的存在性,其中,λ∈R,0〈q〈1,p〉pc≡(N+2)/(N-2)(N〉2).在条件N≤6或N〉6,p〈pN≡(N+1-(2N-3)1/2)/(N-3-(2N-3)1/2)下,证明了存在唯一的λ0,λ0〉0,当λ=λ0时,有唯一的径向奇异解及无穷多个正解。 相似文献
19.
Zhi-ting Xu 《应用数学学报(英文版)》2007,23(4):569-578
Some oscillation theorems are given for the nonlinear second order elliptic equationsum from i,j=1 to N D_i[a_(ij)(x)Ψ(y)||▽y||~(p-2)D_(jy)] c(x)f(y)=0.The results are extensions of modified Riccati techniques and include recent results of Usami. 相似文献