新题征展(20)

A　题组新编1 .已知 z∈ C,解下列方程 :( 1 ) z2 - 5| z| 6 =0( 2 ) z| z| - 5z 6 =0( 3) z| z| - 5| z| 6 =0( 4 ) | z2 | - 5| z| 6 =02 .已知棱长为 a的正方体 ABCD -A1B1C1D1,则( 1 )各棱在平面 AB1D1上的射影长之和为 ;( 2 )各棱与平面 AB1D1所成角之和为;( 3)各面在平面 AB1D1上的射影的面积之和为 ;( 4 )各面与平面 AB1D1所成角之和为.3.( 1 )在实数集 R上定义的函数 f( x) ,对任意α,β有f (α) f (β) =f ( α β2 ) f ( α -β2 ) ,且　 f ( 1 ) =2 ,f ( x) 2 ,则满足条件的一个函数是 .( 2 )已知 f ( x)…     

变量核分数次积分在Hardy空间的有界性

§ 1　 Introduction and main resultsLet Sn- 1 be the unitsphere in Rn(n≥ 2 ) equipped with normalized Lebesgue measure dσ= dσ(z′) .We say that a functionΩ(x,z) defined on Rn× Rnbelongs to L∞ (Rn)× Lr(Sn- 1 )(r≥ 1 ) ,ifΩ(x,z) satisfies the following two conditions,(i) for any x,z∈Rnandλ>0 ,there hasΩ(x,λz) =Ω(x,z) ;(ii)‖Ω‖L∞(Rn)× Lr(Sn- 1) :=supx∈ Rn∫Sn- 1|Ω(x,z′) | rdσ(z′) 1 / r<∞ .For 0 <α相似文献   

非线性抛物方程的时空有限元方法的误差估计

1 引言 本文考虑如下形式的方程 其中,Ω∈R2,0<α≤a(u)≤β,|▽a(u)|≤M,α,βM为正常数.函数f(u)满足:|f(u)|≤ c|u|, (?)∈C(Ω),c为正常数.而且,f(u)是Lipschitz连续函数,即满足|f(u)-|f(v)|≤ L|u-v|,(?)u,v∈C(Ω),L为Lipschitz常数. 利用自适应时空有限元方法求解上述类型的抛物方程,文[1]中对线性模型进行了讨 论,并给出空间L2模误差估计.在[2]中,首次给出了抛物型问题自适应方法的有效性和 可靠性分析,并给出最优L∞(L2)和L∞(L∞o)模误差估计.进一步,[3]3中推广到一般非线     

A Spirallikeness Condition for Analytic Functions

Letα,β,γandρbe real,|α|<π/2,β>0,0≤ρ<1,and letf(z)=z+sum from n=2 to∞ a_nz~nbe analytic in the unit disc E={z:|z|<1}.Futher letJ(α,β,γ,ρ,f(z))=(e~ia(zf’(z)/f(z))-ρcosα)~1-2γ[(e~ia(zf’(z)/f(z)-ρcosα)~2+βcosae~ia(zf’(z)/f(z)(1+zf”(z)/f’(z)-zf’(z)/f(z))]~γ     

含临界指数的拟线性椭圆系统正对称解的存在性（英文）

本文讨论一类拟线性椭圆型系统-Δpu=μ|u|p-2 u|x|p+2αQ(x)(α+β)|x|s|u|α-2 u|v|β+σ1|u|q1-2 u,x∈Ω,-Δpv=μ|v|p-2v|x|p+2βQ(x)(α+β)|x|s|u|α|v|β-2v+σ2|v|q2-2v,x∈Ω,u=v=0,x∈Ω,其中Δpu=div(|▽u|p-2▽u)是p-Laplacian,2≤pN,ΩRN是一个有界光滑区域,0∈Ω,且Ω关于O(N)的一个闭子群G对称,0≤μ,=((N-p)/p)p,σ1,σ2≥0,0≤sp,α,β1满足α+β=p*(s)=(N-s)p/(N-p),pq1,q2p*=Np/(N-p),Q(x)是Ω上的连续G对称函数.应用Palais对称临界原理和变分方法,我们建立了该系统几个全新的正G-对称解的存在性结果.     

在共振点附近的一类二阶泛函微分方程的解析解

在复域C内研究一类包含未知函数迭代的二阶微分方程x″(z)=G(z,x(z),x~2(z),…,x~m(z))解析解的存在性.通过Schr(?)der变换,即x(z)=y(αy~(-1)(z)),把这类方程转化为一种不含未知函数迭代的泛函微分方程α~2y″(αz)y″(z)-αy′(αz)y″(z)= (y′(z))~3G(y(z),y(αz),…,y(α~mz)),并给出它的局部可逆解析解.本文不仅讨论了双曲型情形0<|α|<1和共振的情形(α是一个单位根),而且还在Brjuno条件下讨论了共振点附近的情形(即单位根附近).     

一类振荡积分算子在Wiener 共合空间上的有界性

假设a,b0并且K_(a,b)(x)=(e~(i|x|~(-b)))/(|x|~(n+a))定义强奇异卷积算子T如下:Tf(x)=(K_(a,b)*f)(x),本文主要考虑了如上定义的算子T在Wiener共合空间W(FL~p,L~q)(R~n)上的有界性.另一方面,设α,β0并且γ(t)=|t|~k或γ(t)=sgn(t)|t|~k.利用振荡积分估计,本文还研究了算子T_(α,β)f(x,y)=p.v∫_(-1)~1f(x-t,y-γ(t))(e~(2πi|t|~(-β)))/(t|t|~α)dt及其推广形式∧_(α,β)f(x,y,z)=∫_(Q~2)f(x-t,y-s,z-t~ks~j)e~(-2πit)~(-β_1_s-β_2)t~(-α_1-1)s~(-α_2-1)dtds在Wiener共合空间W(FL~p,L~q)上的映射性质.本文的结论足以表明,Wiener共合空间是Lebesgue空间的一个很好的替代.     

关于全纯映照模的Schwarz引理一点注记

记DC为单位圆盘,B~k C~k为开欧氏单位球,Ω是C~k(或C)中的域.记H_n(D,Ω)为满足一定条件的全纯映照族(或函数族)的全体.作者证明了若,∈Hn(D,D),则|f′(z)|≤(n|z|~(n-1))/(1-|z|~(2n))(1-|f|(z|~2),z∈DD同时,对Hn(D,B~k)中映照的模也得到类似的结果.该结论推广了Pavlovic的相应结果.     

一类带Sobolev-Hardy指数的椭圆型方程组无穷多球对称解的存在性

考虑了一类带Sobolev-Hardy指数的椭圆型方程组{-Δu-μu/|x|2=α/α+β|μ|α-2u|v|β/|x|s+σp/p+q|u|p-2u|v|q,x∈B,-Δu-μu/|x|2=β/α+β|μ|α|v|β-2v/|x|s+σp/p+q|u|p|v|q-2,x∈B,其中0≤μμ,-4,μ=((N-2)~2)/4,σ0,0≤s2,N6+s,α+β=2~*(s)=(2(N-s))/(N-2),p,q≥1,2≤p+q2~*(s),B■R~N为以原点为心的一个开球.利用逼近方法及喷泉定理,得到了上述方程组无穷多个球对称解的存在性.     

单位球上加权Bergman空间的复合型算子

本文给出了Cn中单位球上加权Bergman空间Apα到Bloch型空间βq的加权复合算子Tψ,φ为有界算子和紧算子的简捷充要条件,同时给出了如下结果:(1)若复合算子Cφ在Apα上有界,则Cφ在Apα上紧的充要条件是lim|z|→1-1-|z|/1-|φ(z)|=0.该结果改进了Zhu的相应结果.(2)复合算子Cφ是Apα到βn+1+α+p/p紧算子的充要条件是lim|z|→1-1-|z|/1-|φ(z)|=0.     

Fractional variational problems with the Riesz-Caputo derivative

In this paper we investigate optimality conditions for fractional variational problems, with a Lagrangian depending on the Riesz-Caputo derivative. First we prove a generalized Euler-Lagrange equation for the case when the interval of integration of the functional is different from the interval of the fractional derivative. Next we consider integral dynamic constraints on the problem, for several different cases. Finally, we determine optimality conditions for functionals depending not only on the admissible functions, but on time also, and we present a necessary condition for a pair function-time to be an optimal solution to the problem.     

Gradient Estimates for the Positive Solutions of $$\mathfrak {L}u=0$$ on Self-Shrinkers

In this paper, we investigate the positive solutions of \(\mathfrak {L}u=0\) on a self-shrinker. First, we prove a global gradient estimate for the positive solutions, and obtain a strong Liouville theorem. Then by the generalized Laplacian comparison theorem for the distance function on a self-shrinker, we derive a local gradient estimate for the positive solutions. At last, we collect some applications of the local gradient estimate for the positive solutions on self-shrinkers.     

求参数置信限的一种方法

本文介绍一种找参数精确置信限和置信区间的一般方法,关键想法是在样本空间中定义一个序。本文主要考虑单参数统计模型，对序的优良性（即相应的置信限的优良性）作了讨论，指出应以得分函数的大小为依据在样本空间中定义序。还证明了用最大似然估计定义序得到的置信限是一个单调函数的唯一零点，从而通过解方程算出置信限。     

About measures and nodal systems for which the Hermite interpolants uniformly converge to continuous functions on the circle and interval

We obtain the Laurent polynomial of Hermite interpolation on the unit circle for nodal systems more general than those formed by the n-roots of complex numbers with modulus one. Under suitable assumptions for the nodal system, that is, when it is constituted by the zeros of para-orthogonal polynomials with respect to appropriate measures or when it satisfies certain properties, we prove the convergence of the polynomial of Hermite-Fejér interpolation for continuous functions. Moreover, we also study the general Hermite interpolation problem on the unit circle and we obtain a sufficient condition on the interpolation conditions for the derivatives, in order to have uniform convergence for continuous functions.Finally, we obtain some improvements on the Hermite interpolation problems on the interval and for the Hermite trigonometric interpolation.     

Schur-Ostrowski type theorems revisited

In this paper we extend Schur-Ostrowski theorem on Schur-convex functions from majorized vectors to separable ones. For this, we introduce a generalized Schur-Ostrowski?s condition. We apply the obtained result for cone orderings and group-induced cone orderings. Finally, we give some interpretations for absolutely weak majorization and for group majorization on the space of complex matrices.     

Viscosity solutions for second order integro-differential equations without monotonicity condition: the probabilistic approach

In this paper, we establish a new existence and uniqueness result of a continuous viscosity solution for integro-partial differential equation (IPDE in short). The novelty is that we relax the so-called monotonicity assumption on the driver which is classically assumed in the literature of viscosity solutions of equation with non-local terms. Our method strongly relies on the link between IPDEs and backward stochastic differential equations with jumps for which we already know that the solution exists and is unique for general drivers. In the second part of the paper, we deal with the IPDE with obstacle and we obtain similar results.     

Recent Developments in Robust Portfolios with a Worst-Case Approach

Robust models have a major role in portfolio optimization for resolving the sensitivity issue of the classical mean–variance model. In this paper, we survey developments of worst-case optimization while focusing on approaches for constructing robust portfolios. In addition to the robust formulations for the Markowitz model, we review work on deriving robust counterparts for value-at-risk and conditional value-at-risk problems as well as methods for combining uncertainty in factor models. Recent findings on properties of robust portfolios are introduced, and we conclude by presenting our thoughts on future research directions.     

Numerical accuracy of real inversion formulas for the Laplace transform

In this article, we investigate and compare a number of real inversion formulas for the Laplace transform. The focus is on the accuracy and applicability of the formulas for numerical inversion. In this contribution, we study the performance of the formulas for measures concentrated on a positive half-line to continue with measures on an arbitrary half-line. As our trial measure concentrated on a positive half-line, we take the broad Gamma probability distribution family.     

Three‐point bending tests—Part I: Mathematical study and asymptotic analysis

The goal of this work is to study the static behaviour of a three‐dimensional elastic beam when is subjected to a three‐point bending test. In the first part, under suitable compatibility conditions on the applied forces and on the geometry of the beam, we will prove the existence of a unique solution for the associated contact elastic problem; these conditions of compatibility on the data come from the absence of a Dirichlet condition on the beam boundary. In the second part, we will study the asymptotic behaviour of this problem; in particular, we will deduce the one‐dimensional models associated with the displacement components, and we will give the existence and uniqueness of solution for them. Moreover, we will give an expression for the normal axial stress in the beam which is related to the modulus of rupture of brittle materials. In the final part of the work, we will deal with the regularity of the solution for the bending problem and we will prove some properties of the coincidence set. Copyright © 2011 John Wiley & Sons, Ltd.     

CONTACT PROCESS ON HEXAGONAL LATTICE

In this article, we discuss several properties of the basic contact process on hexagonal lattice H, showing that it behaves quite similar to the process on d-dimensional lattice Zd in many aspects. Firstly, we construct a coupling between the contact process on hexagonal lattice and the oriented percolation, and prove an equivalent finite space-time condition for the survival of the process. Secondly, we show the complete convergence theorem and the polynomial growth hold for the contact process on hexagonal lattice. Finally, we prove exponential bounds in the supercritical case and exponential decay rates in the subcritical case of the process.