一类含临界耦合非线性项的奇异椭圆方程组的正解

本文研究了一类含临界指数与耦合非线性项的奇异椭圆方程组. 利用变分方法与极大值原理, 通过证明对应的能量泛函满足局部的 (PS)c 条件, 得到了这类方程组正解的存在性, 推广了单个方程与方程组中的相应结果.     

R~N中一类(p,q)-Laplacian椭圆方程组的多重正解

研究了一类(p,q)-Laplacian拟线性椭圆方程组问题,利用Nehari流形和LjusternikSchnirelmann畴数理论,探讨了位势函数f(x)如何影响这类方程组正解的个数.     

R^N中—（p,q）-Laplacian拟线性椭圆方程组正解的存在性和多重性

研究了—（p,q）-Laplacian拟线性椭圆方程组.当连续函数V和W在两种情形下,利用Moser迭代技巧和Ljusternik-Schnirelmann畴数理论,建立了方程组正解的存在性和多重性结果.     

基于Nehari等变分法的拟线性方程组多重正解的证明

研究了含有权函数和Hardy-Sobolev临界指标的拟线性方程组,运用Nehari等变分法,证明在一定条件下椭圆方程组正解的存在性以及多重性.     

一类次线性椭圆方程组正解的存在唯一性

考虑半线性椭圆方程组■(1)其中A>0,Ω是有界光滑区域.f,g是定义在R_+~2:=[0,∞)×[0,∞)上的实值函数讨论在满足什么条件下此半线性椭圆方程组存在唯一的正解.     

R~N中含Sobolev临界指数的拟线性椭圆方程组的多重正解

研究了R~N上一类含Sobolev临界指数的p-Laplacian拟线性椭圆方程组.借助位势函数的特性,利用变分方法,通过对Nehari流形进行分解,证明了当参数(λ,μ)属于R~2中某个子集时,该类方程组至少存在2个正解.     

临界非线性椭圆系统的正解［英文］

本文我们借助全空间中无穷远处的方程组,结临界非线性椭圆系统建立一个整体紧性定理.利用此抽象结果及熟知的山路定理证明该系统的正解存在性.     

临界非线性椭圆系统的正解(英文)

本文我们借助全空间中无穷远处的方程组,结临界非线性椭圆系统建立一个整体紧性定理.利用此抽象结果及熟知的山路定理证明该系统的正解存在性.     

含梯度项的椭圆方程组的边界爆破解

研究了含梯度项的椭圆方程组的边界爆破解的性质,其中权函数a(x),b(x)为正并且满足一定的条件.利用上下解的方法及比较原则证明了正解的存在性与唯一性,并得到了边界爆破速率的估计.     

一类退化椭圆方程组的正解的存在性及其应用

本文研究了一类带Ｄｉｒｉｃｈｌｅｔ边值条件的退化椭圆方程组的正解的存在性，所用方法是构造性的，并将所得结果应用到一类生态方程的竞争模型。     

Stein fillability and the realization of contact manifolds

There is an intrinsic notion of what it means for a contact manifold to be the smooth boundary of a Stein manifold. The same concept has another more extrinsic formulation, which is often used as a convenient working hypothesis. We give a simple proof that the two are equivalent. Moreover it is shown that, even though a border always exists, its germ is not unique; nevertheless the germ of the Dolbeault cohomology of any border is unique. We also point out that any Stein fillable compact contact -manifold has a geometric realization in via an embedding, or in via an immersion.

     

On Flat Complete Causal Lorentzian Manifolds

We describe up to finite coverings causal flat affine complete Lorentzian manifolds such that the past and the future of any point are closed near this point. We say that these manifolds are strictly causal. In particular, we prove that their fundamental groups are virtually abelian. In dimension 4, there is only one, up to a scaling factor, strictly causal manifold which is not globally hyperbolic. For a generic point of this manifold, either the past or the future is not closed and contains a lightlike straight line     

A Note on P—Sasakian Manifold

s51.IntroductionLetMbeadifferentiablemanifo1dofdimensionn,ifMadmitsa(l,l)-tensorfieldgl,aPoSitivedefiniteRiemannianmetricg,avectorfieldeandal-formVwhichsatisfythefollow-ingconditions.thensuchamanifoldMiscalledaPara-SasakianmanifoldorbrieflyaP-Sasakianmanifoldby7'.AdatiandK.Matsumoto[ljwhichareconsideredasspecialcaseofanalmostparacontactmanifoldintroducedbyI.Sato[2].WhereVdenotestheoperatorofcovariantdifferentiationwithrespecttothemetrictensorg'X(M)denotesthesetofdifferentiablevectorfiel…     

ON PSEUDOSYMMETRY TYPE HYPERSURFACES OF SEMI-EUCLIDEAN SPACES I

In this paper the authors investigate hypersurfaces M of a semi-Euclidean space Esn+1, n > 4, satisfying (aC + BR) ?H = LkQ(g, Hk), k = 1,2, 3. Using obtained results they show additional curvature properties of investigated hypersurfaces.     

Some remarks about 1-convex manifolds on which all holomorphic line bundles are trivial

We give an abridged proof of an example already considered in [M. Col?oiu, On 1-convex manifolds with 1-dimensional exceptional set, Rev. Roumaine Math. Pures et Appl. 43 (1998) 97-104] of a 1-convex manifold X of dimension 3 such that all holomorphic line bundles on X are trivial. We also point out several mistakes of [Vo Van Tan, On the quasiprojectivity of compactifiable strongly pseudoconvex manifolds, Bull. Sci. Math. 129 (2005) 501-522] concerning this topic.     

Einstein Metrics,Symplectic Minimality,and Pseudo-Holomorphic Curves

An alternative proof of the uniformization theorem for compact two-dimensional riemannian surfaces of genus 0 is proved via the direct methods of the calculus of variation as a minimum problem of the metric-dependent Dirichlet energy in the class of those maps with degree 1. Because of the conformal invariance of the energy-functional and the non compactness of the conformal group on S², concentration of mass for sequences can occur and spheres can split off. Nevertheless this is not the case for appropriate conformaly retransformed minimizing sequences. The main argument is the verification of a condition of the Douglas-type.     

Contactly geodesic transformations of almost-contact metric structures

We introduce the notion of contactly geodesic transformation of the metric of an almost-contact metric structure as a contact analog of holomorphically geodesic transformations of the metric of an almost-Hermitian structure. A series of invariants of such transformations is obtained. We prove that such transformations preserve the normality property of an almost-contact metric structure. We prove that cosymplectic and Sasakian manifolds, as well as Kenmotsu manifolds, do not admit nontrivial contactly geodesic transformations of the metric, which is a contact analog of the well-known result for Kählerian manifolds due to Westlake and Yano.     

ON PSEUDOSYMMETRY TYPE HYPERSURFACES OF SEMI-EUCLIDEAN SPACES Ⅰ

In this paper the authors investigate hypersurfaces M of a semi-Euclidean space Esn+1, n ≥ 4, satisfying (aC +βR). H ＝ LkQ(g, Hk), k ＝ 1,2,3. Using obtained results they show additional curvature properties of investigated hypersurfaces.     

The signature of generalized flag manifolds and applications

Let G be a linear algebraic group over C and P be a parabolic subgroup. We determine the signatures of the flag manifold G/P. As an application, we prove that the nonsingular hypersurfaces of degree 2 in CP^n are prime if n satisfies certain conditions.