Isoperimetric Inequalities on Compact Manifolds

We prove an isoperimetric inequality on compact Riemannian manifolds corresponding to the limit case of a scale of optimal Sobolev inequalities.     

Isoperimetric Inequalities for Random Walks

In this paper some isoperimetric problems are studied, particularly the extremal property of the mean exit time of the random walk from finite sets. This isoperimetric problem is inserted into the set of equivalent conditions of the diagonal upper estimate of transition probability of random walks on weighted graphs.     

两平面凸域的对称混合等周不等式

设K_k(k=i,j)为欧氏平面R~2中面积为A_k,周长为P_k的域,它们的对称混合等周亏格(symmetric mixed isoperimetric deficit)为σ(K_i,K_j)=P_i~2P_j~2-16π~2A_iA_j.根据周家足,任德麟(2010)和Zhou,Yue(2009)中的思想,用积分几何方法,得到了两平面凸域的Bonnesen型对称混合不等式及对称混合等周不等式,给出了两域的对称混合等周亏格的一个上界估计.还得到了两平面凸域的离散Bonnesen型对称混合不等式及两凸域的对称混合等周亏格的一个上界估计,并应用这些对称混合(等周)不等式估计第二类完全椭圆积分.     

体积差的等周不等式

首次提出并建立了凸体的体积差函数的等周不等式,它是经典等周不等式的推广.作为应用,对星体建立了体积差函数的对偶等周不等式和广义对偶等周不等式.     

Rienmannian Submersions and Isoperimetric Inequalities

Isoperimetric constants of the total spaces of Riemannian submersions are estimated in terms of those of the basis and fibers.     

The Gaussian Isoperimetric Inequality and Transportation

Any probability measure on ^d which satisfies the Gaussian or exponential isoperimetric inequality fulfils a transportation inequality for a suitable cost function. Suppose that W (x) dx satisfies the Gaussian isoperimetric inequality: then a probability density function f with respect to W (x) dx has finite entropy, provided that t . This strengthens the quadratic logarithmic Sobolev inequality of Gross (Amr. J. Math 97 (1975) 1061). Let (dx) = e ^–(x) dx be a probability measure on ^d, where is uniformly convex. Talagrand's technique extends to monotone rearrangements in several dimensions (Talagrand, Geometric Funct. Anal. 6 (1996) 587), yielding a direct proof that satisfies a quadratic transportation inequality. The class of probability measures that satisfy a quadratic transportation inequality is stable under multiplication by logarithmically bounded Lipschitz densities.     

Local Isoperimetric Inequalities for Sectors on Surfaces and Cones

On surfaces we give conditions under which the solution of a restricted local isoperimetric problem for sectors with small solid angle is the circular sector and we characterize these surfaces. Also we study this problem for general spherical cones on hypersurfaces in higher dimensional Riemannian manifolds.     

经典等周不等式的又一简单初等的证明

In this short note we will give another simple and elementary proof of the classical isoperimetric inequality in the Euclidean plane.     

Some Isoperimetric Inequalities for Kernels of Free Extensions

If G is a hyperbolic group (resp. synchronously or asynchronously automatic group) which can be expressed as an extension of a finitely presented group H by a finitely generated free group, then the normal subgroup H satisfies a polynomial isoperimetric inequality (resp. exponential isoperimetric inequality).     

关于平面卵形区域的等周亏格上界的几点注记

利用平面卵形区域的Ros'定理及其加强形式,给出平面R²中卵形区域的等周亏格的几个上界估计.     

几个与Ros等周亏格相关的逆Bonnesen型不等式

研究了平面卵形区域的Ros等周亏格问题,利用R~2中卵形区域的Ros定理及其加强形式,著名的等周不等式,给出R~2中卵形区域与Ros等周亏格相关的几个逆Bonnesen型不等式.     

Generalization and sharpness of the power means inequality and their applications

In this paper, we generalize and sharpen the power means inequality by using the theory of majorization and the analytic techniques. Our results unify some optimal versions of the power means inequality. As application, a well-known conjectured inequality proposed by Janous et al. is proven. Furthermore, these results are used for studying a class of geometric inequalities for simplex, from which, some interesting inequalities including the refined Euler inequality and the reversed Finsler-Hadwiger type inequality are obtained.     

Sharp Inequalities for Ratios of Partition Functions of Schrödinger Operators

This paper derives inequalities for multiple integrals from which inequalities for ratios of integrals of heat kernels of certain Schrödinger operators follows. Such ratio inequalities imply inequalities for the partition functions of these operators which extend the spectral gap results proved by R. Bañuelos and P. Méndez-Hernández and B. Davis.     

若干函数不等式探析

针对近几年大学生高等数学竞赛和硕士研究生入学考试中出现的若干有关函数不等式的试题,探讨分析其命题背景,并推广深化相关结果.     

对称随机变量部分和的概率不等式

在对称随机变量分布函数关于原点的值大于或等于二分之一的基础上,阐明对称随机变量的部分和仍是对称随机变量,进一步,给出关于对称随机变量序列部分和的概率不等式.     

Sharp Inequalities for BMO Functions

The purpose of the paper is to study sharp weak-type bounds for functions of bounded mean oscillation. Let 0 p ∞ be a fixed number and let I be an interval contained in R. The author shows that for any φ : I → R and any subset E I of positive measure,For each p, the constant on the right-hand side is the best possible. The proof rests on the explicit evaluation of the associated Bellman function. The result is a complement of the earlier works of Slavin, Vasyunin and Volberg concerning weak-type, L ~p and exponential bounds for the BMO class.     

关于凸函数的新不等式

考虑由Fejér不等式的右边部分生成的差值.通过建立积分恒等式,在导函数满足M-Lipschitz条件和导函数有界这两种情况下,给出这个差值的界的估计.     

Some Improvements on Hermite-Hadamard's Inequalities for $s$-Convex Functions

Using an integral identity for a once differentiable mapping, this paper establishes Hadamard's integral inequalities for $s$-convex and $s$-concave mappings. In particular, our results improve and extend some known ones in the literature. Finally, these inequalities are applied to special means.     

涉及Jensen函数的不等式

引入了Jensen函数及Jensen平均的概念,借助于数学分析和代数工具给出了Jensen函数的分解公式,利用这个公式给出了推广和加强Jensen不等式的一种崭新的思路,作为应用,给出了Jensen不等式成立的一个有趣的充分条件．旨在为数学研究提供一些有用的解析不等式．