共查询到20条相似文献,搜索用时 31 毫秒
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Yu Xiang LI 《数学学报(英文版)》2006,22(2):545-550
We will show in this paper that if A is very close to 1, then
I(M,λ,m) =supu∈H0^1,n(m),∫m|△↓u|^ndV=1∫Ω(e^αn|u|^n/(n-1)-λm∑k=1|αnun/(n-1)|k/k!)dV
can be attained, where M is a compact-manifold with boundary. This result gives a counter-example to the conjecture of de Figueiredo and Ruf in their paper titled "On an inequality by Trudinger and Moser and related elliptic equations" (Comm. Pure. Appl. Math., 55, 135-152, 2002). 相似文献
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The Cauchy problem for a linear 2mth-order Schrōdinger equation ut=-i(-△)^mu, in R^N×R+,u|t=0=u0;m≥1 is an integer,is studied, for initial data uo in the weighted space L^2ρ(R^N),withρ^*(x)=e|x|^a and a=2m/2m-1∈(1,2].The following five problems are studied: (I) A sharp asymptotic behaviour of solutions as t → +∞ is governed by a discrete spectrum and a countable set Ф of the eigenfunctions of the linear rescaled operator B=-i(-△)^m+1/2my·↓△+N/2mI,with the spectrum σ(B)={λβ=-|β|≥0}. (Ⅱ) Finite-time blow-up local structures of nodal sets of solutions as t → 0^- and a formation of "multiple zeros" are described by the eigenfunctions, being generalized Hermite polynomials, of the "adjoint" operator B=-i(-△)^m-1/2my·↓△,with the same spectrum σ(B^*)=σ(B).Applications of these spectral results also include: (Ⅲ) a unique continuation theorem, and (IV) boundary characteristic point regularity issues. Some applications are discussed for more general linear PDEs and for the nonlinear Schr6dinger equations in the focusing ("+") and defocusing ("-") cases ut=-(-△)^mu±i|u|^p-1u,in R^N×R+,where P〉1,as well as for: (V) the quasilinear Schr6dinger equation of a "porous medium type" ut=-(-△)^m(|u|^nu),in R^N×R+,where n〉0.For the latter one, the main idea towards countable families of nonlinear eigenfunctions is to perform a homotopic path n → 0^+ and to use spectral theory of the pair {B,B^*}. 相似文献
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李明融 《数学物理学报(B辑英文版)》2007,27(4):703-734
In this article the author works with the ordinary differential equation u" = |u|^p for some p 〉 0 and obtains some interesting phenomena concerning blow-up, blow-up rate, life-span, stability, instability, zeros and critical points of solutions to this equation. 相似文献
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Chang Xing MIAO You Bin ZHU 《数学学报(英文版)》2008,24(1):17-26
The authors consider the well-posedness in energy space of the critical non-linear system of wave equations with Hamiltonian structure{utt-△u=-F1(|u|^2,|v|^2)u,utt-△u=-F2(|u|^2,|v|^2)u where there exists a function F(λ,μ) such that δF(λ,μ)/δλ=F1(λ,μ).δF(λ,μ)/δμ=F2(λ,μ) By showing that the energy and dilation identities hold for weak solution under some assumptions on the non-linearities, we prove the global well-posedness in energy space by a similar argument to that for global regularity as shown in "Shatah and Struwe's paper, Ann. of Math. 138, 503-518 (1993)". 相似文献
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《数理统计与管理》2019,(3):495-505
本文运用2010-2016年全部A股上市公司样本,系统考察了现金流不确定性对于企业研发投入和企业价值的影响及对于研发投入与企业价值相关关系的调节作用。随后,依据企业生命周期理论和融资约束理论将样本分组,进一步的验证企业生命周期和融资约束程度差异对于现金流不确定性调节作用的效果差异。研究发现,在当前"赢家效应"较强的背景下,现金流的不确定性能够促进企业研发投入,显著提升企业价值,且能够对研发投入与企业价值的关系起到正向调节作用。进一步的,本文发现现金流不确定性发挥的正向调节作用在成长期企业和融资约束程度高的企业作用显著,而在成熟期和融资约束程度低的企业不显著。本文的研究结论不仅丰富了有关现金流和研发创新领域的相关文献,而且可以为我国资本市场的完善和企业的研发创新行为提供参考。 相似文献
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作为|a|+|b|≥|a+b|的应用,不等式|a|1+|a|+|b|1+|b|≥|a+b|1+|a+b|的证明是大家熟知的;事实上,它可推广成:|a|1+|a|+|b|1+|b|+|c|1+|c|≥|a+b+c|1+|a+b+c|;利用f(x)=x1+x在(0,+∞)上是增函数及|a|+|b|≥|a+b|不难给其证明,从略;通过类比,有以下重要结论:定理 若|a|<1,|b|<1,|c|<1,则(1)|a|1-|a|+|b|1-|b|+|c|1-|c|≥|a+b+c|1-13|a+b+c|;若|… 相似文献
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一、发现
本方法依据这样一个事实:绝对值小于1的任意实数自乘后小于自身,即:|a|〈1,则:1〉|a|〉|a|^2〉|a|^3〉…〉|a|^n,用数学语言来描述就是:limn→∞an^=0. 相似文献
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ZHENG Tingting ZHAO Junning 《偏微分方程(英文版)》2009,(3):199-204
In this note we study the nonexistence of nontrivial global solutions on S = R^N × (0,∞) for the following inequalities:|u|t≥△(|u|^m-1u)+|u|^q and |u|t≥div(|△u|^p-2△|u|)+|u|^q.When m,p,q satisfy some given conditions, the nonexistence of nontrivial global solution is proved, without taking their traces on the hyperplans t = 0 into account. 相似文献
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由于汇率、利率、商品价格的变化以及双渠道供应链关系的复杂性,企业的现金流存在较大的波动性。本文研究双渠道销售模式下,制造商对现金流进行套期保值的决策问题。重点关注垄断企业在拥有一个分销商和线上销售的双渠道销售模式下,并利用内部融资将现金流用于提高生产效率时,如何根据现金流的波动程度、市场需求、替代产品敏感系数以及批发价格进行套期保值决策。研究了双渠道销售模式下制造商的均衡问题,比较了两种决策下的均衡解,并通过数值分析给出了直观的结论:市场最大需求与替代产品敏感系数增加时,企业更倾向于选择套期保值;现金流波动程度与批发价格增加时,企业更倾向于不选择套期保值。 相似文献
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资金,是企业管理的永恒话题。离开了现金流,所有的企业行为都只是一句空话。2010年以来,我国货币政策持续紧缩,融资环境急剧变化,企业面临经营风险加大、资金不足及来自大宗原材料成本、人力成本等上涨的双重压力。现金流吃紧,让企业资金风险悄然抬头。 相似文献