第39届IMO-5的简证

题目　设Ｉ为△ＡＢＣ的内心,Ｋ、Ｌ、Ｍ分别为△ＡＢＣ的内切圆在ＢＣ、ＣＡ、ＡＢ上的切点,已知通过点Ｂ与ＭＫ平行的直线分别与直线ＬＭ及ＬＫ交于Ｒ、Ｓ两点,求证∠ＲＩＳ为锐角．证明　记△ＡＢＣ的内切圆半径为ｒ,∵　ＲＳ∥ＭＫ且△ＭＫＬ为切点三角形,故　∠ＲＳＫ＝∠ＭＫＬ＝∠ＬＭＡ,∴　Ｓ、Ｌ、Ｍ、Ｂ四点共圆．故　ＲＢ·ＲＳ＝ＲＭ·ＲＬ．但Ｒ是圆Ｉ外一点,ＲＭ·ＲＬ＝ＲＩ２－ｒ２,∴　　ＲＢ·ＲＳ＝ＲＩ２－ｒ２（１）同理可知　ＳＢ·ＳＲ＝ＳＩ２－ｒ２（２）由（１）、（２）有ＲＩ２＋ＳＩ２－２ｒ２＝ＲＳ…     

二阶非线性边值问题解的存在唯一性定理

考虑方程ｙ‘’＋ｆ（ｔ，ｙ，ｙ‘）＝０在边值条件ｙ（ａ）＝Ａ，ｙ（ｂ）＝Ｂ下解的存在唯一性，要求ｆ满足Ｌ＾２－Ｃａｒａｔｈｅｏｄｏｒｙ条件，在Ｌ＾２空间中利用映象原理得到解唯一存在的最优结果。     

关于局部紧空间的闭Lindelof映象

本文给出了两类局部紧空间闭Ｌ（Ｌｉｎｄｅｌｏｆ）映象的内部特征,证明了空间Ｘ是仿紧局部紧空间的闭Ｌ映象当且发Ｘ是具有σ－局部有限ｋ系的ｋ空间,由此得到在ｋ′空间类中,偏紧局部紧空间的闭Ｌ映象等价于偏紧局部紧空间的商ＳＬＪ央象,同时不证明了空间Ｘ是局部紧度量空间的闭Ｌ映象当且Ｘ是具有σ－局部有限紧ｋ网的Ｆｒｅｃｈｅｔ空间。     

多值(S)型映象度理论以及不动点定理

本文的主要目的是推广Browder[1,2]的结果. 本文分四部分,首先我们介绍多值(S)及其(S)₊型映象以及多值(S),(S)₊型极限映象.它们包含许多单调型映象为特例,如极大单调映象.有界伪单调以及有界广义伪单调映象.在第二部分我们定义(S)型映象的伪度以及(S)₊映象的度,它们是Browder[1,2]中度的推广.作为应用,我们利用第二部分中的度理论来研究多值算子方程解的存在性(见第三节),获得一些新的不动点定理.     

用构造法解一类最值问题

用构造法解一类最值问题文家金（四川省安岳一中６４２３６７）问题１设折线：Ａ１Ａ２…Ａｎ＋１的长为定值Ｌ：与直线Ａ１Ａｎ＋１所围成的ｎ十１边形的面积记为Ｓ（ｎ≥２）．（１）为何种折线时Ｓ最大？（２）若Ａ１，Ａｎ＋１为定点，问为何种折线时Ｓ最大？结论：（...     

关于HSOLSSOM（2^nu^1）的谱

本文讨论型为２＾ｎｕ＾１的有对称正交侣的带洞自正交拉丁方（ＨＳＯＬＳＳＯＭ（２＾ｎｕ＾１））的谱。证明当ｎ≤９时,ＨＳＯＬＳＳＯＭ（２＾ｎｕ＾１）存在的充分必要条件是ｕ为偶数且ｎ≥３ｕ／２＋１;当ｎ≥２６３时,若ｕ为偶数且ｎ≥２（ｕ－２）,则ＨＳＯＬＳＳＯＭ（２＾ｎｕ＾１）存在。     

Clifford鞅的b_p~ 权不等式

本文在Ｃｌｉｆｏｒｄ代数值函数ψ满足ｂ＋ｐ条件下讨论了关于测度ｄμ＝ψｄν的条件期望的基本性质，证明了Ｃｌｉｆｏｒｄ代数值鞅的一些基本结果，包括Ｃｌｉｆｏｒｄ鞅的极大算子ｆ的弱（１，１）与强（ｐ，ｐ）不等式以及均方算子Ｓ（ｆ）的Ｌ２有界性，Ｓ（ｆ）与ｆ的Φ等价性．     

算子方程解的稠密性及半线性系统的近似可控性

本文利用Ｂａｎａｃｈ不动点定理和Ｓｃｈａｕｄｅｒ不动点定理研究如下算子方程解的稠密性：ｙ＝ｙ０＋ＬＦ（ｙ）＋ＬＨ（ｖ）（其中，Ｌ、Ｈ为线性算子，Ｆ为非线性算子），然后，利用所得结论讨论Ｂａｎａｃｈ空间内的半线性系统：ｘ＇（ｔ）＋Ａ（ｔ）ｘ（ｔ）＝ｆ（ｔ，ｘ（ｔ）＋Ｂｕ（ｔ）的近似可控性。     

Z_2-商的秩为r的超椭圆纤维化曲面的斜率

设Ｓ是一般型的相对极小曲面，ｆ：Ｓ→Ｃ是亏格ｇ的超椭圆纤维化．本文中我们证明了如果 Ｓ的代数基本群的垂直部分的极大挠 ２商为，那么其斜率且等号成立仅当 Ｓ上的超椭圆对合所诱导的二次复盖的分歧除子 Ｒ仅有（ｒ＋１→，＋１）（当ｒ为偶数）型奇点，或（ｒ＋２→ｒ＋２）（当ｒ为奇数）型奇点．     

Z_2-商的秩为r的超椭圆纤维化曲面的斜率

设Ｓ是一般型的相对极小曲面，ｆ：Ｓ→Ｃ是亏格ｇ的超椭圆纤维化．本文中我们证明了如果 Ｓ的代数基本群的垂直部分的极大挠 ２商为，那么其斜率且等号成立仅当 Ｓ上的超椭圆对合所诱导的二次复盖的分歧除子 Ｒ仅有（ｒ＋１→，＋１）（当ｒ为偶数）型奇点，或（ｒ＋２→ｒ＋２）（当ｒ为奇数）型奇点．     

A REPRESENTATION FORMULA RELATED TO SCHR(O)DINGER OPERATORS

Schr(o)dinger operator is a central subject in the mathematical study of quantum mechanics.Consider the Schrodinger operator H = -△ V on R, where △ = d2/dx2 and the potential function V is real valued. In Fourier analysis, it is well-known that a square integrable function admits an expansion with exponentials as eigenfunctions of -△. A natural conjecture is that an L2 function admits a similar expansion in terms of "eigenfunctions" of H, a perturbation of the Laplacian (see [7], Ch. Ⅺ and the notes), under certain condition on V.     

On a class of self-similar processes with stationary increments in higher order Wiener chaoses

We study a class of self-similar processes with stationary increments belonging to higher order Wiener chaoses which are similar to Hermite processes. We obtain an almost sure wavelet-like expansion of these processes. This allows us to compute the pointwise and local Hölder regularity of sample paths and to analyse their behaviour at infinity. We also provide some results on the Hausdorff dimension of the range and graphs of multidimensional anisotropic self-similar processes with stationary increments defined by multiple Wiener–Itô integrals.     

Qualitative Analysis of Bifurcating Solutions in the Lengyel-Epstein Model

One of the most fundamental problems in theoretical biology is to explain the mechanisms by which patterns and forms are created in the＇living world. In his seminal paper ＂The Chemical Basis of Morphogenesis＂, Turing showed that a system of coupled reaction-diffusion equations can be used to describe patterns and forms in biological systems. However, the first experimental evidence to the Turing patterns was observed by De Kepper and her associates（1990） on the CIMA reaction in an open unstirred reactor, almost 40 years after Turing＇s prediction. Lengyel and Epstein characterized this famous experiment using a system of reaction-diffusion equations. The Lengyel-Epstein model is in the form as follows     

(0,1 ;0)-INTERPOLATION ON INFINITE INTERVAL (-∞, +∞)

In this paper, we study the explicit representation and convergence of (0, 1; 0)-interpolation on infinite interval, which means to determine a polynomial of degree ≤ 3n - 2 when the function values are prescribed at two set of points namely the zeros of Hn(x) and H′n(x) and the first derivatives at the zeros of H′n(x).     

On a class of Riemann surfaces

It is considered the class of Riemann surfaces with dimT1 = 0, where T1 is a subclass of exact harmonic forms which is one of the factors in the orthogonal decomposition of the spaceΩH of harmonic forms of the surface, namely The surfaces in the class OHD and the class of planar surfaces satisfy dimT1 = 0. A.Pfluger posed the question whether there might exist other surfaces outside those two classes. Here it is shown that in the case of finite genus g, we should look for a surface S with dimT1 = 0 among the surfaces of the form Sg\K , where Sg is a closed surface of genus g and K a compact set of positive harmonic measure with perfect components and very irregular boundary.     

CONTENTS OF VOLUME 30

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Instructions for contributions

正Applied Mathematics-A Journal of Chinese Universities,Series B(Appl.Math.J.Chinese Univ.,Ser.B)is a comprehensive applied mathematics journal jointly sponsored by Zhejiang University,China Society for Industrial and Applied Mathematics,and Springer-Verlag.It is a quarterly journal with     

Journal of Mathematical Research with Applications Guide for Authors

正Journal overview:Journal of Mathematical Research with Applications(JMRA),formerly Journal of Mathematical Research and Exposition(JMRE)created in 1981,one of the transactions of China Society for Industrial and Applied Mathematics,is a home for original research papers of the highest quality in all areas of mathematics with applications.The target audience comprises:pure and applied mathematicians,graduate students in broad fields of sciences and technology,scientists and engineers interested in mathematics.     

Staircase transportation problems with superadditive rewards and cumulative capacities

A cumulative-capacitated transportation problem is studied. The supply nodes and demand nodes are each chains. Shipments from a supply node to a demand node are possible only if the pair lies in a sublattice, or equivalently, in a staircase disjoint union of rectangles, of the product of the two chains. There are (lattice) superadditive upper bounds on the cumulative flows in all leading subrectangles of each rectangle. It is shown that there is a greatest cumulative flow formed by the natural generalization of the South-West Corner Rule that respects cumulative-flow capacities; it has maximum reward when the rewards are (lattice) superadditive; it is integer if the supplies, demands and capacities are integer; and it can be calculated myopically in linear time. The result is specialized to earlier work of Hoeffding (1940), Fréchet (1951), Lorentz (1953), Hoffman (1963) and Barnes and Hoffman (1985). Applications are given to extreme constrained bivariate distributions, optimal distribution with limited one-way product substitution and, generalizing results of Derman and Klein (1958), optimal sales with age-dependent rewards and capacities.To our friend, Philip Wolfe, with admiration and affection, on the occasion of his 65th birthday.Research was supported respectively by the IBM T.J. Watson and IBM Almaden Research Centers and is a minor revision of the IBM Research Report [6].