一类奇异拟线性椭圆型方程组的可解性

研究了一类P-Laplacian方程组边值问题正径向整体解的存在性和唯一性.首先,利用隐函数定理证明了该问题的局部解的存在性与唯一性,以及解对初值的连续依赖性.最后,证明了该问题存在唯一的正径向整体解.     

全平面上的高斯曲率方程

本文用Ｓｃｈａｕｄｅｒ不动点定理证明了一维Ｋ≥０的解、二维Ｋ≥０的径向解的存在性，同时证明了当Ｋ≤０时，在无穷远处有不同渐近性的Ｋ所对应的极大解的渐近性，并给出了径向解的刻画，推广了前人结果．     

球外部区域上一类椭圆边值问题的正径向解

研究了一类椭圆边值问题在球外部区域上正径向解的存在性,当非线性项f（u）关于u超线性或次线性增长的情形,获得了该问题正径向解的存在性.     

带非线性阻尼项的欧拉——泊松方程组径向对称解的爆破问题

研究了N维空间中带非线性阻尼项的欧拉-泊松方程组的径向对称解的爆破问题.当t≥0时,定义了泛函H(t)和测试函数φ(r),采用积分法得到了当H(0)满足一定条件时在非光滑边界条件下方程组的非平凡径向对称解将在有限时间内发生爆破.采用相似的方法也得到了一维空间中径向对称解的相应结论.     

复线性微分方程解的导数的Julia集的径向分布

本文主要研究一类复线性微分方程的整函数解的导数的Julia集的径向分布.在适当条件下,本文证明这类复微分方程的整函数解及其导数的Julia集具有相似的径向分布,并找到了它们的下界,从而改进了最近的一些相关结果.     

一类由Hermitian Yang-Mills度量导出的半线性偏微分方程（英文）

本文研究了由一类Hermitian Yang-Mills度量的极限行为所导出的半线性方程的边值问题与全局解的径向对称性质.使用极大值原理与Leray-Schhauder不动点定理,我们得到了这个方程在R²平面中全局C²解的径向对称性与这个方程的Dirichlet问题在任意有界区域内C^2,α解的存在性.     

带自由边界的可压缩欧拉与欧拉-泊松方程组径向对称解的爆破北大核心CSCD

本文在R^(N)(N=2,3)中研究描述流向外部真空的可压缩流体的欧拉与欧拉-泊松方程组径向对称解的爆破.在分离流体与真空的连续自由边界条件下考虑其自由边值问题.对于径向对称的欧拉方程组,证明若初始流平均向外流动,则其光滑解将在有限时刻爆破.对于带有斥力与弛豫项的单极与双极径向对称欧拉-泊松方程组,证明若某个与初始动量有关的加权泛函适当大,则其光滑解将在有限时刻爆破。     

基于Gauss全局径向基函数的近岸浅水变形波高数值计算新方法

应用Gauss全局径向基函数来模拟波浪浅水变形波高变化方程中的未知函数,经实例分析探讨得到了一种可用于求解该方程数值解的新方法,并将其计算结果与常用数值分析方法得到的数值解相互对比印证,证明了基于Gauss全局径向基函数法计算结果的正确性.经验证,Gauss径向基函数法的平均计算误差相比其他方法均要小,表明该方法拥有更高的计算精度.同时,根据Gauss全局径向基函数的逼近结果,得出了浅水变形波高变化微分方程数值解的拟合函数,在实际工程中,可以利用该拟合函数来代替原方程的解析解,研究成果可为求解近岸浅水区域波浪运动提供一种新思路.     

带有临界指标的非线性Poisson-Schr(o)dinger系统解的不存在性

本文研究一个在强非线性项阻碍临界增长条件下Poisson-Schr(o)dinger(PS)系统的孤波解.分别利用变分不等式和Pohozaev型讨论,证明了径向对称解和非平凡解的不存在性.     

二阶半线性椭圆方程的径向解

本文讨论了无界域上的二阶半线性椭圆方程的径向解，给出了古典解的性质，诸如存在或非存在性，唯一性以及解的估计式等，这些性质清晰地描绘了古典解的性态。     

单形的径向平均体

本文研究了单形的p次径向平均体RpK,证明了单形的p次径向平均体位似于其差分体,得到了Rp(Rq)与Rq(Rp)是相等,并且单形的p次径向平均体的Brunn-Minkowski不等式及唯一性.     

Separated totally convex spaces

In this paper we define for every totally convex space a suitable topology, the radial topology. We prove that a morphism in the category TC^sep of separated totally convex spaces is an epimorphism if and only if its image is dense in the radial topology, and that TC^sep is the full subcategory of TC generated by its Hausdorff objects. These results remain valid for finitely totally convex spaces when the radial topology is replaced by the distance-radial topology.Dedicated to Karl Stein     

Existence of radial solutions for an asymptotically linear p-Laplacian problem

We prove that an asymptotically linear Dirichlet problem which involves the p-Laplacian operator has multiple radial solutions when the nonlinearity has a positive zero and the range of the ‘p-derivative’ of the nonlinearity includes at least the first j radial eigenvalues of the p-Laplacian operator. The main tools that we use are a uniqueness result for the p-Laplacian operator and bifurcation theory.     

Nekhoroshev theorem for perturbations of the central motion

In this paper we prove a Nekhoroshev type theorem for perturbations of Hamiltonians describing a particle subject to the force due to a central potential. Precisely, we prove that under an explicit condition on the potential, the Hamiltonian of the central motion is quasiconvex. Thus, when it is perturbed, two actions (the modulus of the total angular momentum and the action of the reduced radial system) are approximately conserved for times which are exponentially long with the inverse of the perturbation parameter.     

Improved stability estimates and a characterization of the native space for matrix-valued RBFs

In this paper we derive several new results involving matrix-valued radial basis functions (RBFs). We begin by introducing a class of matrix-valued RBFs which can be used to construct interpolants that are curl-free. Next, we offer a characterization of the native space for divergence-free and curl-free kernels based on the Fourier transform. Finally, we investigate the stability of the interpolation matrix for both the divergence-free and curl-free cases, and when the kernel has finite smoothness we obtain sharp estimates. An erratum to this article can be found at     

Scale invariance structures of the critical and the subcritical Hardy inequalities and their improvements

In this paper, we study classical Hardy inequalities, both in the subcritical case on the whole space and the critical case on a ball. Two Hardy inequalities are quite different from each other in view of their forms, scaling structures and optimal constants. Nevertheless we show that, when the exponents are chosen appropriately, both inequalities are equivalent at least in the radial setting. A transformation which connects two inequalities is a key in our argument. As an application, we improve the critical Hardy inequality on a ball by using the improved subcritical inequality on the whole space.     

Asymptotic behavior for critical Patlak–Keller–Segel model and a repulsive–attractive aggregation equation

In this paper we study the long time asymptotic behavior for a class of diffusion–aggregation equations. Most results except the ones in Section 3.3 concern radial solutions. The main tools used in the paper are maximum principle type arguments on mass concentration of solutions, as well as energy method. For the Patlak–Keller–Segel problem with critical power m=2−2/d$m=2-2/d$, we prove that all radial solutions with critical mass would converge to a family of stationary solutions, while all radial solutions with subcritical mass converge to a self-similar dissipating solution algebraically fast. For non-radial solutions, we obtain convergence towards the self-similar dissipating solution when the mass is sufficiently small. We also apply the mass comparison method to another aggregation model with repulsive–attractive interaction, and prove that radial solutions converge to the stationary solution exponentially fast.     

Radial Moore graphs of radius three

The maximum number of vertices in a graph of specified degree and diameter cannot exceed the Moore bound. Graphs achieving this bound are called Moore graphs. Because Moore graphs are so rare, researchers have considered various relaxations of the Moore graph constraints. Since the diameter of a Moore graph is equal to its radius, one can consider graphs in which the condition on the diameter is relaxed, by one, while the condition on the radius is maintained. Such graphs are called radial Moore graphs. It has previously been shown that radial Moore graphs exist for all degrees when the radius is two. In this paper, we extend this result to radius three. We also construct examples that settle the existence question for a few new cases, and summarize the state of knowledge on the problem.     

Radial and non-radial decompositions of profit change: With an application to Indian banking

Grifell-Tatje and Lovell [Grifell-Tatje, E., Lovell, C.A.K., 1999. Profits and productivity. Management Science 45, 1177–1193] made significant contributions to the literature on the extended radial DEA framework by decomposing profit change into six mutually exclusive components. Their approach, however, poses two basic problems. First, the radial estimates on these components might give conflicting signals about the direction of profit change after the full radial efficiencies are achieved when slacks are present. Second, evaluations of these components, using base-period prices as weights, can be potentially misleading. To address these concerns, we first introduce non-radial DEA models, and then, provide a few strong theoretical arguments in favor of using as weights either current-period prices or an average price covering both periods to value the contributions of each of these components. The Indian banking sector is taken as a case study to illustrate the radial and non-radial decompositions of profit change so as to empirically examine the role of competition on profit change and its drivers. Our broad empirical results are as follows: first, radial and non-radial models yield diametrically opposite results on the contributions of various components. Second, the increasing efficiency change trends in all ownership groups after 2002 indicate that the Government reform process instituted on the banking industry has had a favorable effect on the performance of the Indian banking sector. Third, despite the fact that nationalized banks are the oldest banks, their output and resource allocation behaviors do not reflect their learning experience.     

球面间流体流动考虑流动惯性的近似解

本文利用球坐标下的Navier-Stokes方程式,采用迭代近似解法,求出了考虑流动惯性时的球面间流动的压力分布、速度分布以及流量的解析式。并利用此式可直接导出平行圆板间径向层流的相应解析表达式,它与文献[3],[4]中所提供的相应结果是完全一致的。