关于一阶拟线性方程的整体解

对于非线性偏微分方程,通常局部可解性比较容易得到,而整体解问题则复杂得多.近年来,关于非线性偏微分方程的整体可解性已得到很多研究结果.比如[1]、[2]中讨论了非线性波动方程的整体可解性.[3]中讨论了某种双曲型方程组的整体可解性.[4]中讨论了某种非线性椭圆型方程的整体不可解性.也有大量工作讨论整体广义解的存在性.这些结果都是关于微分方程的初值问题或边值问题的整体可解性.但是如果我们期望得到全空间的整体解,那么如本文所得到的结果那样,微分方程本身是否存在这种整体解就是一个很值得研究的问题. 我们称方程的在全空间具有直到方程阶数的连续导数的解为全正则解.     

两个正规p-超可解子群的积

本文研究了两个正规的p-超可解子群的积构成的极小非P-超可解群的结构的问题.利用有限群论和群类论的一些基本方法,获得了两个正规的p-超可解子群的积仍为P-超可解群的一些充分条件,并推广了文[1]中关于超可解群的情况.     

Baer超可解性定理的两点应用

本文通过Baer的超可解性定理、证明了有限生成的超Abel群的两个超可解性条件,包含了Hup－pert和Baer关于有限超可解群的结果[3]．     

非性性奇异边值问题

对一类奇异两点边值问题,在很一般的条件下,证明了摄动问题的可解性与一类全连续映象不动点的存在性是等价的,并且给出了摄动问题的可解性与原问题的可解性之间的关系．     

非线性奇异边值问题

对一类奇异两点边值问题,在很一般的条件下,证明了振动问题的可解性与一类全连续映象不动点的存在性是等价的,并且给出了振动问题的可解性与原问题的可解性之间的关系。     

关于丢番图方程ax~2 by~2=cP~n

本文解决了题设方程的可解性及可解时解的表示这一基本的问题，由此改进了已有结果.     

一般形式的一阶椭圆型偏微分方程组拟线性Riemann-Hilbert问题

在文[1,2,3]中,E.Wegert和L.V.Wolfersdorf等人讨论了一类全纯函数的拟线性Riemann-Hilbert问题在Hardy空间中的可解性,在文[4]中,讨论了广义解析函数的拟线性Riemann-Hilbert问题,同样得到该边值问题在H2类解空间中的可解性.本文在前面研究工作的基础上,对一般形式的一阶椭圆型偏微分方程组拟线性Riemannn-Hilbert问题作了更深入的讨论,在适当的假设条件下,应用积分算子理论,函数论方法及不动点原理,证明了该边值问题在相应的泛函空间中同样是可解的.     

关于p-超可解群

本文讨论p-超可解群的几个特征性质.主要是两个.一是利用p-局部子群刻画p-超可解性,它与关于超可解群的Baer的定理有联系,而后者在超可解群理论中占有重要地位,这在[2]中可看到.二是用两个特征子群的p-幂零性来刻画p-起可解性.本文的群都指有限群. 以下由R.Baer表述的引理具有基本的重要性. 引理1 设L是群G的极小正规子群,p||L.如果(G/C_G(L))’与(G/C_G(L))~(p-1)都是p-群,则|L|=p.     

一类含有分数阶导数的二自由度耦合系统

研究了一类含有小扰动具有分数阶导数的二自由度耦合振子的振动问题.首先对含有由Riemann Liouville定义的分数阶导数的振动方程组构造渐近解,利用多重尺度法,得到振动问题的可解性条件.然后在可解性条件下,得到分数阶指数、系数及小参数对振动的影响,并求得渐近解.最后研究了该解的稳定性,发现定常解都是稳定的     

带有非退化不变对称双线性型的有限维可解李代数

本文讨论复数域上带有非退化不变对称双线性型的,可裂的有限维可解李代数的性质及结构.给出了不可分解的非退化可解李代数的定义.证明了本文所讨论的李代数可以分解成不可分解的非退化可解理想的正交直和.对于不可分解的非退化可解李代数,给出了它关于极大环面子代数的根空间分解;讨论了根空间的结构及运算关系;证明了它的 Cartan 子代数的交换性,并给出了 Cartan子代数的结构.     

Solvable andl-solvablel-groups

It is possible to consider the question of solvability of a lattice-ordered group via two different approaches — one involves the satisfying of appropriate commutator laws by thel-group and the other involves the study of the derived series ofl-ideals of thel-group. The first method defines solvability strictly in terms of group operations, while the second deals with the lattice-ordering as well; hence, solvability andl-solvability. This paper deals with some of the distinctions between these two families ofl-group varieties.Presented by L. Fuchs.     

On some classes of coefficient inverse problems for parabolic systems of equations

We examine the question on solvability in the Sobolev spaces of coefficient inverse problems for parabolic systems of equations with the overdetermination conditions on a collection of surfaces. Under certain conditions on the geometry of the domain and the boundary operators, the local solvability of the problem is proven. It is demonstrated that the conditions on the boundary operators are sharp and that, in some cases, the problem is not unconditionally solvable.     

Regularity and solvability of linear differential operators in Gevrey spaces

We are interested in the following question: when regularity properties of a linear differential operator imply solvability of its transpose in the sense of Gevrey ultradistributions? This question is studied for a class of abstract operators that contains the usual differential operators with real‐analytic coefficients. We obtain a new proof of a global result on compact manifolds (global Gevrey hypoellipticity implying global solvability of the transpose), as well as some results in the non‐compact case by means of the so‐called property of non‐confinement of singularities. We provide applications to Hörmander operators, to operators of constant strength and to locally integrable systems of vector fields. We also analyze a conjecture stated in a recent paper of Malaspina and Nicola, which asserts that, in differential complexes naturally arising from locally integrable structures, local solvability in the sense of ultradistributions implies local solvability in the sense of distributions. We establish the validity of the conjecture when the cotangent structure bundle is spanned by the differential of a single first integral.     

关于一类条件投入产出方程的可解性定理

本文引入了一类基于企业消耗与市场需求的条件投入产出方程,在适当的基本假设下,用非线性分析方法对这类方程分别包含存在性,连续性及满射性的可解性问题作了初步研究.由此获得本文的主要结果并给出相应的经济解释.     

On optimal shape design of systems governed by mixed Dirichlet-Signorini boundary value problems

A problem for finding optimal shape for systems governed by the mixed unilateral boundary value problem of Dirichlet-Signorini-type is considered. Conditions for the solvability of the problem are stated when a variational inequality formulation and when a penalty method is used for solving the state problem in question. The asymptotic relation of design problems based on these two formulations is presented. The optimal shape design problem is discretized by means of finite element method. The convergence results for the approximation are proved. The discretized versions are then formulated as a non-linear programming problem. Results of practical computations of the problem in question are reported.     

On some classes of inverse problems of recovering a source function

In the article we examine the question on solvability, uniqueness, and some qualitative properties of solutions to inverse problems of recovering point sources (the right-hand sides of a special form) in a one-dimensional parabolic equation. The values of a solution at some collection of points are taken as the overdetermination conditions. Examples are exposed that show that the uniqueness fails without additional conditions on the mutual disposition of sources and measurement points.     

Corner singularity for transmission problems in three dimensions

For a transmission problem for the Laplace operator the unique solvability is proved in natural Sobolev spaces in the case when edges and corners are present. The behaviour of the solution near the corner is reduced to the question when an explicitely given meromorphic family of one-dimensional integral operators on a geodesic polygon on the two sphere has a non-trivial kernel.     

A problem with operators of fractional differentiation in boundary condition for mixed-type equation

We consider a question on unique solvability of a boundary-value problem with fractional derivatives for a mixed-type equation of second order. We prove first a uniqueness theorem. The existence theorem is proved by means of reduction to Fredholm equation of the second kind, and its unconditional solvability follows from the uniqueness of solution.     

Solvability for Riemann-Stieltjes integral boundary value problems of Bagley-Torvik equations at resonance

In this paper, we study the solvability for Riemann-Stieltjes integral boundary value problems of Bagley-Torvik equations with fractional derivative under resonant conditions. Firstly, the kernel function is presented through the Laplace transform and the properties of the kernel function are obtained. And then, some new results on the solvability for the boundary value problem are established by using Mawhin''s coincidence degree theory. Finally, two examples are presented to illustrate the applicability of our main results.     

On some three-dimensional variants of Goursat and Darboux problems for higher-order hyperbolic equations with dominating principal parts

Some three-dimensional variants of Goursat and Darboux problems for higher-order hyperbolic equations with dominating principal part are set and investigated. Conditions to the problems' data which in some cases ensure the well-posedness of the problem in question and in other cases, despite the solvability of the problem, imply the presence of an infinite set of linearly independent solutions of corresponding homogeneous problem, are found. We consider both generalized and classical solutions. Translated from Sovremennaya Matematika i Ee Prilozheniya (Contemporary Mathematics and Its Applications), Vol. 51, Differential Equations and Their Applications, 2008.