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.     

R3中四面体的Bonnesen型等周不等式

该文主要研究R3中四面体的Bonnesen型与逆Bonnesen型等周不等式.对于R3中给定的四面体,利用其表面积、体积、内切球半径及外接球半径之间的关系,构造出两个重要的几何不等式,得到了四面体的一些Bonnesen型等周不等式与等周不等式的新的简单证明.更进一步地,通过讨论四面体等周亏格的上界估计,获得了两个用内切...     

关于四面体的Bonnesen型等周不等式

主要研究几何体的Bonnesen型等周不等式.得到了两个关于四面体的Bonnesen型等周不等式;进一步地,给出了关于四面体的等周不等式的一个简单证明.     

R~n中的一个Bonnesen型不等式

研究了n维欧氏空间中凸体K的等周亏格的下界估计,即Bonnesen型不等式.首先加强了Lutwak中得到的关于凸体K的p-平均不等式,用此得到一个用凸体K的均质积分及调和均质积分表示的等周亏格的下界估计.     

平面Bonnesen型不等式的几点注记

本文研究了平面紧域的Bonnesen型不等式.利用紧域及其凸包的周长和面积得到一些新的Bonnesen型不等式以及两个用最大内切圆半径与最小外接圆半径表示的Bonnesen型不等式.     

两个新的Bonnesen型不等式

本文研究了Bonnesen型不等式.利用积分几何方法,得到了两个新的Bonnesen型不等式.     

R3中四面体的几个新Bonnesen型不等式

离散的等周问题在积分几何与凸几何中扮演着重要角色.等周亏格的稳定性可以由Bon-nesen型不等式和逆Bonnesen型不等式来刻画.该文主要研究R3中四面体的Bonnesen型不等式和逆Bonnesen型不等式,获得了四面体的几个新的Bonnesen型不等式,并提供了不同于Sturm[15]关于四面体的等周不等式的一...     

平面两凸域的Bonnesen型对称混合不等式

本文利用积分几何中的Poincare运动公式和Blaschke运动公式估计平面上两域K_0和k_1的对称混合等周亏格△_2(K_0,K_1),得到了对称混合等周不等式和一些Bonnesen型对称混合不等式,其中一个不等式加强了Kotlyar的不等式.此外我们还得到了一些逆Bonnesen型对称混合不等式,其条件比著名的Bottema不等式的弱.     

关于平面凸多边形的一个Bonnesen型不等式

本文探索了关于平面凸多边形的Bonnesen型不等式.利用分析方法,先构造一个解析函数的不等式,进而得到了一个关于平面凸多边形的Bonnesen型不等式.     

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.     

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.     

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.     

Schur-Convex Functions and Isoperimetric Inequalities

In this paper, we establish some analytic inequalities for Schur-convex functions that are made of solutions of a second order nonlinear differential equation. We apply these analytic inequalities to obtain some geometric inequalities.

     

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.     

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.     

Isoperimetric Inequalities for Soluble Groups

We approach the question of which soluble groups are automatic. We describe a class of nilpotent-by-Abelian groups which need to be studied in order to answer this question. We show that the nilpotent-by-cyclic groups in this class have exponential isoperimetric inequality and so cannot be automatic.     

Isoperimetric Type Inequalities and Hypersurface Flows

New types of hypersurface flows have been introduced recently with goals to establish isoperimetric type inequalities in geometry. These flows serve as efficient paths to achieve the optimal solutions to the problems of calculus of variations in geometric setting. The main idea is to use variational structures to develop hypersurface flows which are monotonic for the corresponding curvature integrals (including volume and surface area). These new geometric flows pose interesting but challenging PDE problems. Resolution of these problems have significant geometric implications.     

Isoperimetric Inequalities for a Wedge-Like Membrane

For a wedge-like membrane, Payne and Weinberger proved in 1960 an isoperimetric inequality for the fundamental eigenvalue which in some cases improves the classical isoperimetric inequality of Faber–Krahn. In this work, we introduce “relative torsional rigidity” for this type of membrane and prove new isoperimetric inequalities in the spirit of Saint-Venant, Pólya–Szeg?, Payne, Payne–Rayner, Chiti, and Talenti, which link the eigenvalue problem with the boundary value problem in a fundamental way.     

Second Order Isoperimetric Inequalities of Split Extensions

In this paper, we set up the general upper bounds for the second order dehn functions of split extensions.AMS Subject Classification (2000): 20F32This work was partially supported by China State Education Ministry SEYTF Funds and China Guangdong Province GDNSF (000864) Fund.