Asymptotics in nonlinear evolution system with dissipation and ellipticity on quadrant

In this paper, we consider an initial boundary value problem for some nonlinear evolution system with dissipation and ellipticity. We establish the global existence and furthermore obtain the Lp (p?2) decay rates of solutions corresponding to diffusion waves. The analysis is based on the energy method and pointwise estimates.     

Small‐strain heterogeneous elastoplasticity revisited

The elastoplastic quasi‐static evolution of a multiphase material—a material with a pointwise varying yield surface and elasticity tensor, together with interfaces between the phases—is revisited in the context of conservative globally minimizing movements. Existence is shown, and classical evolutions are recovered under natural constraints on the plastic dissipation potential. Special attention is paid to the interfaces where the correct dissipation has to be enforced on the interfaces. Further, the evolution is shown to be a limit of that obtained for a model with linear isotropic hardening as the hardening becomes vanishingly small. The duality between plastic strains and admissible stresses is also revisited for Lipschitz boundaries, and its role in deriving a classical evolution is circumscribed. © 2012 Wiley Periodicals, Inc.     

格上点式p.q.度量的乘性

本文在可数多个分子格的乘积上构造了一个乘积点式p·q·度量函数,从而证明了点式p·q·度量分子格的可数积是可点式p·q·度量化的.     

Criteria for Pointwise Growth and Their Role in Invasion Processes

This article is concerned with pointwise growth and spreading speeds in systems of parabolic partial differential equations. Several criteria exist for quantifying pointwise growth rates. These include the location in the complex plane of singularities of the pointwise Green’s function and pinched double roots of the dispersion relation. The primary aim of this work is to establish some rigorous properties related to these criteria and the relationships between them. In the process, we discover that these concepts are not equivalent and point to some interesting consequences for nonlinear front invasion problems. Among the more striking is the fact that pointwise growth does not depend continuously on system parameters. Other results include a determination of the circumstances under which pointwise growth on the real line implies pointwise growth on a semi-infinite interval. As a final application, we consider invasion fronts in an infinite cylinder and show that the linear prediction always favors the formation of stripes in the leading edge.     

C~n中超球上p-Bloch空间的点乘子

讨论了Cn 中超球上p Bloch空间Bp 上的点乘子 .根据p的不同情况得到Bp 空间所有的点乘子 ,对Bp 空间的点乘子进行了完整的刻划 .     

格上点式一致结构的刻划与点式度量化定理

本文通过对格上远域映射,特别是△-映射和＊-映射的性质的研究,给出了格上点式一致结构的若干简明刻划,证明了几个重要的格上点式度量化定理,并提出了与格上点式度量理论相协调的若干分离性公理.     

Ergodic theorems for noncommutative dynamical systems

Recently, E.C. Lance extended the pointwise ergodic theorem to actions of the group of integers on von Neumann algebras. Our purpose is to extend other pointwise ergodic theorems to von Neumann algebra context: the Dunford-Schwartz-Zygmund pointwise ergodic theorem, the pointwise ergodic theorem for connected amenable locally compact groups, the Wiener's local ergodic theorem for ₊ ^d and for general Lie groups.     

Spatial behavior for some non-standard problems in linear thermoelasticity without energy dissipation

In the present paper we consider a prismatic cylinder occupied by an anisotropic and homogeneous compressible linear thermoelastic material within the framework of the linear theory of thermoelasticity without energy dissipation. The cylinder is subject to zero body force and heat supply and zero lateral specific boundary conditions and the motion is induced by a time-dependent displacement and thermal displacement specified pointwise over the base. Further, the motion is constrained such that the displacement, thermal displacement, velocity and temperature variation at points in the cylinder and at a prescribed time are in given proportions to, but not identical with, their respective initial values. It is shown that certain integrals of the solution spatially evolve with respect to the axial variable. Conditions are derived that show the integrals exhibit alternative behavior and in particular for the semi-infinite cylinder that there is either at least exponential growth or at most exponential decay, provided the elasticity tensor is positive definite or strongly elliptic.     

线性时滞微分方程的点态退化(英文)

本文讨论了线性时滞微分方程的点态退化问题.借助于矩阵的有关知识,我们给出了判定n阶时滞微分方程点态退化的充分必要条件及代数判据.     

Recurrence and Almost Periodicity in Transformation Groups

In [5] Gottschalk comments that an interesting question is to find conditions under which pointwise recurrence in a transformation group (X,T) implies pointwise almost periodicity. In this paper we show that if in a transformation group (X,T), the phase space X is connected locally compact and Hausdorff and T is generative and each point xεX is of P-characteristic 0 for each replete semi-group P in T, then the existence of a single recurrent point implies that (X,T) is pointwise recurrent and each orbit closure is minimal. This implies of course from a general result of Gottschalk and Hedlund that the transformation group is pointwise almost periodic. The condition P-characteristic 0 is weaker than pointwise equicontinuity even when the phase space is compact--see example (4.6) at the end.     

Local and pointwise error estimates of the local discontinuous Galerkin method applied to the Stokes problem

We prove local and pointwise error estimates for the local discontinuous Galerkin method applied to the Stokes problem in two and three dimensions. By using techniques originally developed by A. Schatz [Math. Comp., 67 (1998), 877-899] to prove pointwise estimates for the Laplace equation, we prove optimal weighted pointwise estimates for both the velocity and the pressure for domains with smooth boundaries.

     

偶数维的线性化Navier—Stokes方程解之逐点估计

道德对偶数维线性化Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程的格林函数作出估计，再用格林函数得出了其解的逐点估计。     

On projectively related Einstein metrics in Riemann-Finsler geometry

In this paper we study pointwise projectively related Einstein metrics (having the same geodesics as point sets). We show that pointwise projectively related Einstein metrics satisfy a simple equation along geodesics. In particular, we show that if two pointwise projectively related Einstein metrics are complete with negative Einstein constants, then one is a multiple of another. Received: 28 October 1999 / Revised: 10 January 2000 /Published online: 18 June 2001     

Selection principles for maps of several variables

We show that a pointwise precompact sequence of maps from the n-dimensional rectangle into a metric semigroup, whose total variations in the sense of Vitali, Hardy and Krause are uniformly bounded, contains a pointwise convergent subsequence. We present a variant of this result for maps with values in a reflexive separable Banach space with respect to the weak pointwise convergence of maps.     

逐点伪轨跟踪性质及其应用

本文给出紧致度量空间逐点伪轨跟踪性质的定义,该定义是伪轨跟踪性质定义的推广.作为应用,证明如下结论:(i)若f具有逐点伪轨跟踪性质,且对任意k∈Z ,fk为链转换的,那么对任意k∈Z ,fk为开集转换;(ii)若f具有逐点伪轨跟踪性质,且对任意n∈Z ,fn为链转换的,则f具有初始敏感依赖性质;(iii)若f为开集混合的,且具有逐点伪轨跟踪性质,那么f具有性质P;(iv)设f:(X,d)→(X,d)是同胚映射,那么f具有逐点伪轨跟踪性质当且仅当移位映射σf具有逐点伪轨跟踪性质.     

Herz型Besov空间的点态乘子及应用

作者研究了Herz型Besov空间的点态乘子 ,并利用此点态乘子证明了一类拟微分算子在Herz型Besov空间上的有界性     

格上点式仿紧性

本文在拓扑分子格（ＴＭＬ）上提出一种仿紧性，它以格上点式紧性［３］为特款，讨论了它在ＴＭＬ上的几种不同的表现形式以及它与正规性的关系．     

Pointwise error estimates for a stabilized Galerkin method: non-selfadjoint problems

Highly localized pointwise error estimates for a stabilized Galerkin method are provided for second-order non-selfadjoint elliptic partial differential equations. The estimates show a local dependence of the error on the derivative of the solution u and weak dependence on the global norm. The results in this paper are an extension of the previous pointwise error estimates for the self-adjoint problems. In order to provide pointwise error estimates in the presence of the first-order term in the differential equations, we prove that the stabilized Galerkin solution is higher order perturbation to the Ritz projection of the true solutions. Then, we proceed to obtain pointwise estimates using the so-called discrete Green’s function. Application to error expansion inequalities and a posteriori error estimators are briefly discussed.     

M-P广义逆A_x~+的按点连续性

在A_x对x按点连续的条件下,本文讨论了A_x的M-P广义逆A_x~+对x的按点连续性,并且在第3节给出了在积分方程中的一些应用.