Minimal Complex Surfaces with Levi–Civita Ricci-flat Metrics

This is a continuation of our previous paper [14]. In [14], we introduced the first Aeppli–Chern class on compact complex manifolds, and proved that the(1, 1) curvature form of the Levi–Civita connection represents the first Aeppli–Chern class which is a natural link between Riemannian geometry and complex geometry. In this paper, we study the geometry of compact complex manifolds with Levi–Civita Ricci-flat metrics and classify minimal complex surfaces with Levi–Civita Ricci-flat metrics.More precisely, we show that minimal complex surfaces admitting Levi–Civita Ricci-flat metrics are K¨ahler Calabi–Yau surfaces and Hopf surfaces.     

一个新的Loop代数及其对Levi谱系的应用

本文基于loop代数A₁的一个子代数,构造了一个新的loop代数G;通过作一个适宜的Lax对变换,成功地将G应用于Levi等谱问题上,求得了Levi谱系的可积耦合,这种方法可以普遍地应用。     

半空间中次调和函数的Phragmn-Lindelf定理及应用

本文利用调和函数的Carleman公式,结合Levi的方法,在半空间中证明了次调和函数的Phragmn-Lindelf定理.作为Phragmn-Lindelf定理的应用,本文引入了半空间中的C类函数,并且得到了次调和函数属于C类函数的一个充分必要条件,从而推广了Ahlfors和Levi等的经典结果.     

Levi族的Lax组非线性化

文[1]研究Levi族的Lax表示.今进一步讨论其Lax组的非线性化.设λ_1…,λ_N是Levi特征值问题的N个不同的特征值,那么φ_j(?)(φ_(1j),φ_(2j))~T是相应于特征值λ_j的特征函数,j=1,…,N.(?)=(?)/(?)x,q、r为势函数,x在所论区间Ω内变化. 浓缩(1)为向量形式:     

φ-自由n-李代数的结构

对φ-自由n-李代数的结构进行了研究,得到了特征零域上φ-自由伽李代数的分类定理及Levi 分解定理,同时也得到了任意域上n-李代数可解的等价条件.     

连续系数倒向随机微分方程最小解的Levi定理

本文研究了倒向随机微分方程解的连续依赖性问题.利用文献[4]中使用的方法,提出并证明了连续系数的一维倒向随机微分方程最小解的Levi定理,推广了文献[10]中的相应结果.     

发展方程族Lax表示的广义结构*

本文给出非线性发展方程族的一个生成格式(该格式包含了保谱族与非保谱族作为其两个特殊情况),并提供该格式下发展方程族Lax表示的广义结构.最后,作为应用,我们讨论了Levi族发展方程.     

sl(3,κ)正则幂零表示投射模的Lowey序列

基域k是特征为5的代数闭域,李代数g=sl(3,k).当p-特征函数χ为正则幂零且具有标准Levi型时,本文得到了g的主不可分解模的Lowey序列及其单模自扩张的维数.     

so(5,k)主不可分解模的Loewy序列

设k是特征为素数的代数闭域,李代数g=so(5,k).当p-特征函数χ为次正则幂零且具有标准Levi型时,得到g的主不可分解模的Lowey序列.     

一类新的对称自对偶李代数

本文刻划了一类幂零根基为二步幂零李代数的新的非可解对称自对偶李代数.当其Levi因子同构于sl(2,C)时,用半单李代数的表示理论具体构造了它们.最后,给出了2中对称自对偶李代数是CS李代数的一个判别准则.     

SYMMETRY CONSTRAINT OF THE LEVI EQUATIONS BY BINARY NONLINEARIZATION

In this paper, the translation of the Lax pairs of the Levi equations is presented. Then a symmetry constraint for the Levi equations is given by means of binary nonlinearization method. The spatial part and the temporal parts of the translated Lax pairs and its adjoint Lax pairs of the Levi equations are all constrainted as finite dimensional Liouville integrable Hamiltonian systems. Finally, the involutive solutions of the Levi equations are presented.     

Beppo Levi’s Analysis of the Paradoxes

This paper presents and comments the content of a note by Beppo Levi on logical paradoxes. Though the existence of this contribution is known, very little analysis of it is available in the literature. I put the emphasis on Levi’s usage of “elementation procedures” for solving the set-theoretical paradoxes, which is the most original part of Levi’s approach to the topic.     

On the Levi and Lebesgue properties

The paper is devoted to a question if the Levi property is preserved by direct sums and quotients. The three-space problem for the Levi and Lebesgue properties in topological Riesz spaces is also investigated.     

The Levi Monge-Ampère equation: Smooth regularity of strictly Levi convex solutions

We prove smoothness of strictly Levi convex solutions to the Levi equation in several complex variables. This equation is fully non linear and naturally arises in the study of real hypersurfaces in ℂⁿ⁺¹, for n ≥ 2. For a particular choice of the right-hand side, our equation has the meaning of total Levi curvature of a real hypersurface ℂⁿ⁺¹ and it is the analogous of the equation with prescribed Gauss curvature for the complex structure. However, it is degenerate elliptic also if restricted to strictly Levi convex functions. This basic failure does not allow us to use elliptic techniques such in the classical real and complex Monge-Ampère equations. By taking into account the natural geometry of the problem we prove that first order intrinsic derivatives of strictly Levi convex solutions satisfy a good equation. The smoothness of solutions is then achieved by mean of a bootstrap argument in tangent directions to the hypersurface.     

Levi Classes of Quasivarieties of Groups with Commutator Subgroup of Order p

Algebra and Logic - The Levi class generated by the class ? of groups is the class of all groups in which the normal closure of each element belongs to ?. We describe Levi classes...     

Levi decompositions of a linear algebraic group

If G is a connected linear algebraic group over the field k, a Levi factor of G is a reductive complement to the unipotent radical of G. If k has positive characteristic, G may have no Levi factor, or G may have Levi factors which are not geometrically conjugate. In this paper we give some sufficient conditions for the existence and conjugacy of the Levi factors of G.     

Integral Representations,Differentiability Properties and Limits at Infinity for Beppo Levi Functions

The first aim in the present paper is to give an integral representation for Beppo Levi functions on R ⁿ. Our integral representation is an extension of Sobolev's integral representation given for infinitely differentiable functions with compact support. As applications, continuity and differentiability properties of Beppo Levi functions are studied.Our second aim in this paper is to study the existence of limits at infinity for Beppo Levi functions. We also consider the existence of fine-type limits at infinity with respect to Bessel capacities, which yields the radial limit result at infinity.     

Graphs with prescribed Levi form trace

Abstract We prove existence and uniqueness of a viscosity solution of the Dirichlet problem related to the prescribed Levi mean curvature equation, under suitable assumptions on the boundary data and on the Levi curvature of the domain. We also show that such a solution is Lipschitz continuous by proving that it is the uniform limit of a sequence of classical solutions of elliptic problems and by building Lipschitz continuous barriers. Keywords: Levi mean curvature, Quasilinear degenerate elliptic PDE’s, Viscosity solutions, Comparison principle, Global Lipschitz estimates     

Sur le probleme de Levi dans certains fibres

In this paper, we reduce the Levi Problem for open sets in a locally trivial holomorphic bundle on a Stein manifold with compact homogeneous fibre, to the Levi Problem in the fibres of the bundle.