伪黎曼空间型中的2-调和类空子流形

本文研究了伪黎曼空间型中2-调和类空子流形的有关性质.利用活动标架法和Hopf原理,证明了伪脐2-调和类空子流形Mn是极大的,以及如果Mn是紧致的,那么Mn是全测地的,从而推广了[5,7]中的结果.     

靶流形为齐次流形的弱次椭圆Q调和映射的正则性

该文证明了靶流形为齐次流形的弱次椭圆Q调和映射是内部正则的，这里Q是定义域的 齐次维数。这一结果推广了Hajlasz和Strzelecki的相应结果[2].作为推论得到了靶流形为齐次流形的p维p调和映射的正则性.     

关于局部对称伪黎曼流形中的2-调和类空子流形

研究局部对称伪黎曼流形中的2-调和类空子流形,得到了这类子流形成为极大的Pinching现象及推广的J．Simons型积分不等式．     

黎曼流形到伪黎曼流形的调和映照（Ⅰ）

获得了从黎曼流形到伪黎曼流形的调和映照的一个充要条件，并给出了Ｂｏｃｈｎｅｒ公式。     

伪黎曼空间型的2一调和类空子流形

用活动标架法给出常曲率的伪黎曼流形的类空子流形为2-调和的充要条件,研究平均曲率为零的一些条件.     

Finsler流形间调和映射的一个刚性定理

把无焦点黎曼流形的概念推广到了Finsler流形中.通过在无焦点Finsler流形上构造凸函数,得到了Finsler流形间调和映射的一个刚性定理.     

Finsler流形间调和映射的第2变分

给出了Finsler流形间非蜕化映射的能量泛函的第1和第2变分公式, 并利用变分公式得到了从Finsler流形到Riemann流形的非常值稳定调和映射的若干不存在性定理.     

一般伪黎曼流形中的2-调和类空子流形

本文研究了一般伪黎曼流形中的2-调和类空子流形的有关性质.利用活动标架法和Hopf原理,给出了2-调和子流形是极大的几个充分条件,得到一个Simons型积分不等式并推广了相关结果.     

V-流形间的2-调和映照

本文将２－调和映照从黎曼流形推广到Ｖ－流形,获得了２－调和映照的第一变分和第二变分,得到了２－调和映照成为调和映照的一些充分条件,讨论了Ｖ－流形上２－调和映照的复合映照。     

迷向映照和伪Veronese流形

本文讨论了伪Riemann流形之间的迷向映照。作为从伪Riemann球面到伪Riemann球面的极值浸入的新例子,本文从伪Riemann球面之间的迷向调和映照中确定了所有的伪Veronese流形。最后,利用某些几何量来刻划双曲类空的Veronese流形。     

Superconvergence of a finite element method for the biharmonic equation

Ciarlet‐Raviart's scheme is a finite element method for solving the mixed formulation of the biharmonic equation. So far, there has been no superconvergence for the vorticity from this method if a general rectangular mesh is used. In this article, we deal with the biquadratic elements under the uniform rectangular mesh and prove for the first time a superconvergence for the vorticity. © 2002 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 18: 420–427, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/num.10010     

On a spatial generalization of the Kolosov–Muskhelishvili formulae

The main goal of this paper is to construct a spatial analog to the Kolosov–Muskhelishvili formulae using the framework of the hypercomplex function theory. We prove a generalization of Goursat's representation theorem for solutions of the biharmonic equation in three dimensions. On the basis of this result, we construct explicitly hypercomplex displacement and stress formulae in terms of two monogenic functions. Copyright © 2008 John Wiley & Sons, Ltd.     

Landau's theorems for biharmonic mappings (II)

In this paper, we derive five new versions of Landau‐type theorems for biharmonic mappings of unit disk. Moreover, we prove that all five results are sharp when the bounds are equal to 1. Copyright © 2016 John Wiley & Sons, Ltd.     

Schwarzian derivative, integral means, and the affine and linear invariant families of biharmonic mappings

In this paper we discuss the properties of the Schwarzian derivative, integral means and the affine and linear invariant families of biharmonic mappings. First, we introduce the Schwarzian derivative S(F) for biharmonic mappings F = ∣z∣²G + H, and obtain several necessary and sufficient conditions for S(F) to be analytic. Second, we introduce the subordination of biharmonic mappings and obtain inequalities for integral means of subordinate biharmonic mappings. Finally, we introduce the affine and linear invariant families of biharmonic mappings and prove several estimates related to the Jacobian of functions in these invariant families.     

Biharmonic maps in two dimensions

Biharmonic maps between surfaces are studied in this paper. We compute the bitension field of a map between surfaces with conformal metrics in complex coordinates. As applications, we show that a linear map from Euclidean plane into ${(\mathbb{R}^2, \sigma^2dwd \bar w)}$ is always biharmonic if the conformal factor σ is bianalytic; we construct a family of such σ, and we give a classification of linear biharmonic maps between 2 spheres minus a point. We also study biharmonic maps between surfaces with warped product metrics. This includes a classification of linear biharmonic maps between hyperbolic planes and some constructions of many proper biharmonic maps into a circular cone or a helicoid.     

On conformal biharmonic immersions

This paper studies conformal biharmonic immersions. We first study the transformations of Jacobi operator and the bitension field under conformal change of metrics. We then obtain an invariant equation for a conformal biharmonic immersion of a surface into Euclidean 3-space. As applications, we construct a two-parameter family of non-minimal conformal biharmonic immersions of cylinder into and some examples of conformal biharmonic immersions of four-dimensional Euclidean space into sphere and hyperbolic space, thus providing many simple examples of proper biharmonic maps with rich geometric meanings. These suggest that there are abundant proper biharmonic maps in the family of conformal immersions. We also explore the relationship between biharmonicity and holomorphicity of conformal immersions of surfaces.      

Triharmonic morphisms between Riemannian manifolds

Polyharmonic functions have been studied in various fields. There are maps between Riemannian manifolds called harmonic morphisms and biharmonic morphisms that preserve harmonic functions and biharmonic functions respectively. In this paper, we introduce the notion of k-polyharmonic morphisms as maps that preserves polyharmonic functions of order k. For k = 3, we obtain several characterizations of triharmonic morphisms. We also give some relationships among harmonic, biharmonic, and triharmonic morphisms, and a relationship between triharmonic morphisms and p-harmonic morphisms.     

Dirichlet Problem,Univalency and Schwarz Lemma for Biharmonic Mappings

In this paper, we shall discuss the family of biharmonic mappings for which the maximum principle holds. As a consequence of our study, we present Schwarz Lemma for certain class of biharmonic mappings. Also we discuss the univalency of certain class of biharmonic mappings.     

A note on the reflection principle for the biharmonic equation and the Stokes system

In this note, we discuss the reflection principle of the Stokes system in a half space for the threedimensional case, and of the biharmonic equation. Admitting different boundary conditions, we use the reflection principle to prove uniqueness of solutions of the Stokes system or the biharmonic equation in weightedLq-spaces     

Remarks on biharmonic hypersurfaces in space forms

We consider closed biharmonic hypersurfaces in a Euclidean sphere and prove a rigidity result under a suitable condition on the scalar curvature. Moreover, we establish an integral formula involving the position vector for biharmonic hypersurfaces in space forms. As an application of this formula, we reobtain a result concerning the closed biharmonic hypersurfaces in Euclidean spheres that lie in a closed hemisphere.