The Cardinal of the Set of Non-quasi-regular Elements in a Ring

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具临界指数椭圆方程-Δu=λ_κu |u|~(2~*-2)u f(x,u)非平凡多解存在性

本文利用山路引理以及P．L．Lions的集中紧性原理,给出了具临界指数2*且涉及任意特征值λk 的Dirichlet问题-△u=λku |u|2*-2u f(x,u)一对非平凡解的存在性定理,其中次临界扰动项 f(x,t)可以是关于变量t的非线性项．     

Viscosity Iteration in CAT(κ) Spaces

We study the approximation of fixed points of nonexpansive mappings in CAT(κ) spaces. We show that the iterative sequence generated by the Moudafi's viscosity type algorithm converges to one of the fixed points of the nonexpansive mapping depending on the contraction applied in the algorithm.     

Voter model in a random environment in ? d

We consider the voter model with flip rates determined by {?? _e , e ?? E _d }, where E _d is the set of all non-oriented nearest-neighbour edges in the Euclidean lattice ? ^d . Suppose that {?? _e , e ?? E _d } are independent and identically distributed (i.i.d.) random variables satisfying ?? _e ? 1. We prove that when d = 2, almost surely for all random environments, the voter model has only two extremal invariant measures: ?? ₀ and ?? ₁.     

A chromaticity-brightness model for color images denoising in a Meyer’s “u + v” framework

A variational model for imaging segmentation and denoising color images is proposed. The model combines Meyer’s “u+v” decomposition with a chromaticity-brightness framework and is expressed by a minimization of energy integral functionals depending on a small parameter \(\varepsilon >0\). The asymptotic behavior as \(\varepsilon \rightarrow 0^+\) is characterized, and convergence of infima, almost minimizers, and energies are established. In particular, an integral representation of the lower semicontinuous envelope, with respect to the \(L^1\)-norm, of functionals with linear growth and defined for maps taking values on a certain compact manifold is provided. This study escapes the realm of previous results since the underlying manifold has boundary, and the integrand and its recession function fail to satisfy hypotheses commonly assumed in the literature. The main tools are \(\Gamma \)-convergence and relaxation techniques.     

The Brownian snake and solutions of Δu=u 2 in a domain

Summary We investigate the connections between the path-valued process called the Brownian snake and nonnegative solutions of the partial differential equation u=u ² in a domain of ^d . In particular, we prove two conjectures recently formulated by Dynkin. The first one gives a complete characterization of the boundary polar sets, which correspond to boundary removable singularities for the equation u=u ². The second one establishes a one-to-one correspondence between nonnegative solutions that are bounded above by a harmonic function, and finite measures on the boundary that do not charge polar sets. This correspondence can be made explicit by a probabilistic formula involving a special class of additive functionals of the Brownian snake. Our proofs combine probabilistic and analytic arguments. An important role is played by a new version of the special Markov property, which is of independent interest.     

THE STRUCTURE OF RAPIDLY DECAYING SOLUTIONS OF △u f(u) = 0 in R~n

1IntroductionInthispaper,westudythesingularpositivesolutionsofinR(n>2),wheref(u)islocallyLipschtizcontinuouson[0, co)andf(u)20.Byasingularpositivesolutionof(1.1)-(1.2)wemeanthesolutionwhichsatisfies(1.1)-(l.2)inR{0}andtendsto coattheorigin.Bytheresults…     

Approximate solution of u′=–A2u using a relation between exp(–tA2) and exp(itA)

Let A be a positive definite operator in a Hilbert space and consider the initial value problem for u _t =–A² u. Using a representation of the semi group exp(–A² t) in terms of the group exp(iAt) we express u in terms of the solution of the standard heat equation w _t = w _yy , with initial values v solving the initial value problem for v _y = iAv. This representation is used to construct a method for approximating u in terms of approximations of v. In the case that A is a 2^nd order elliptic operator the method is combined with finite elements in the spatial variable and then reduces the solution of the 4th order equation for u to that of the 2^nd order equation for v, followed by the solution of the heat equation in one space variable.     

Some properties of solutions ofu″+a(t) f (u)=0

Monatshefte für Mathematik -     

Spontaneous violation of spatial parity in dense baryonic matter in a generalized U(2)L×U(2)R sigma model

Based on a generalized U(2) _L ×U(2) _R sigma model describing ground and excited states of scalar and pseudoscalar meson singlets and triplets, we investigate the conditions for spatial parity violation for dense baryonic matter in the hadron phase. We introduce’ t Hooft-type vertices into the model for violating the U(1) _A symmetry of quantum chromodynamics by the anomaly. At large values of the chemical potential, broken-parity states can appear in the model, which corresponds to condensation of pseudoscalar fields. We give the conditions on the parameters of the generalized sigma model that determine the transition to the phase with spontaneously broken parity. For different signs of the constants of two’ t Hooft-type vertices, either pseudoscalar isotriplets or isosinglets undergo condensation.     

Complex behaviour in a production–distribution model

The purpose of this paper is to show how the cascaded structure of a production–distribution chain can produce a wide variety of dynamic behaviours. Despite the apparent simplicity of the chain, the bounded rationality of human decision making interferes with the information feedbacks, nonlinearities and time delays of the system to produce exceedingly complex behaviour. When simulated with realistic parameter values, the model can exhibit stationary periodic, quasiperiodic as well as chaotic and hyperchaotic motions. Lyapunov exponents are used to characterize the different types of behaviour. Repeated simulation reveals how the profile of operating cost is related to the modes of behaviour and to the conditions that generate chaos. Detailed maps of parameter space graphically show the influence of inventory control policies upon dynamics and costs. The analyses illustrate why it is so difficult for decision makers to “navigate” in low-cost policy parameter regions. Suggestions are made for decision heuristics that avoid high-cost, unstable solutions.     

Über Automorphismenbahnen von Elementen u≠O mit (ad u)3=αad u in endlichdimensionalen einfachen komplexen Lie-Algebren

In this paper we study certain semisimple elements in simple complex Koecher-Tits-constructions from Jordan-triplesystems. Let L be a finite dimensional simple complex Lie-Algebra and u O an element in L with (ad u)³=-ad u. Then there is a compact real form L of L, which contains u. The involutorial automorphism id_L+2 (ad_Lu)² of L induces a Cartan-decomposition of a real form L (u) of L and this gives us a criterion of conjugacy under Aut L for two such elements u₁, u₂L.Using this result, we show that the number of conjugacy classes of elements uL (u O) with (ad u)³=ad u (\{O}, under Aut L is equal to the number of similarity classes of Jordantriplesystems, the Koecher-Tits-construction of which is isomorphic to L. The corresponding data are finally listed for all possible types of L.     

On a nonlinear wave equation involving the term −∂∂x(μ(x,t,u,6ux62)ux): Linear approximation and asymptotic expansion of solution in many small parameters

In this paper, we consider the following nonlinear Kirchhoff wave equation (1)$\{\begin{array}{c}{u}_{tt}?\frac{?}{?x}\left(\mu (x,t,u,{6u_{x}6}^2)u_x\right)=f(x,t,u,u_x,u_t)\text{,}0<x<1,0<t<T\text{,}\hfill \\ u(0,t)=g_0\left(t\right)\text{,}u(1,t)=g_1\left(t\right)\text{,}\hfill \\ u(x,0)={\stackrel{?}{u}}_0\left(x\right)\text{,}{u}_t(x,0)={\stackrel{?}{u}}_1\left(x\right)\text{,}\hfill \end{array}$ where ${\stackrel{?}{u}}_0$, ${\stackrel{?}{u}}_1$, $\mu$, $f$, $g_0$, $g_1$ are given functions and ${6u_{x}6}^2={\int }_0^1{u}_x^2(x,t)dx$. First, combining the linearization method for nonlinear term, the Faedo–Galerkin method and the weak compact method, a unique weak solution of problem (1) is obtained. Next, by using Taylor’s expansion of the function $\mu (x,t,y,z)$ around the point $(x,t,y_0,z_0)$ up to order $N+1$, we establish an asymptotic expansion of high order in many small parameters of solution.     

关于拟线性抛物型方程b(u)u_t=[a(u)u_x]_x反问题拟解的存在性问题

本文在 [1 ]中“ut=[a(u) ux]x的一个反问题”的基础上 ,解决了 b(u) ut=[a(u) ux]x 反问题拟解的存在性问题