Dimensions of spaces of homogeneous zero regression polynomials

Simple formulas are proved for the dimensions of vector spaces of homogeneous zero regression polynomials. A simplified characterization of these polynomials is proved.     

On homogeneity and small extensions of models of the theory of linear ordering

Some properties concerning homogeneity and the existence of small extensions proved earlier for models of superstable theories, are proved here for models of the theory of linear ordering.     

Products of exponentials of hermitian and complex symmetric matrices

A conjecture involving exponentials of Hermitian matrices is stated, and proved when one of the matrices has rank at most one. As a consequence, the complete conjecture is proved when the matrices are 2×2. A second conjecture involving exponentials of complex symmetric matrices is also stated, and completely proved when the matrices are 2×2. The two conjectures have similar structures but require quite different techniques to analyze.     

关于格的极小生成元集

本文证明了格的极小生成元集一定是最小生成元集且只能是非零完全并既约元全体，证明了分配格具有最小生成元集的必要条件是它满足并无限分配律．本文还证明了完全Ｈｅｙｔｉｎｇ代数具有最小生成元集当且仅当它是强代数格，证明了完备格是强代数格当且仅当它和它的对偶格均是具有最小生成元集的分配格．     

Homotopy connectedness theorems for submanifolds of Sasakian manifolds

The homotopy connectedness theorem for invariant immersions in Sasakian manifolds with nonnegative transversal q-bisectional curvature is proved. Some Barth-Lefschetz type theorems for minimal submanifolds and (k, ?)-saddle submanifolds in Sasakian manifolds with positive transversal q-Ricci curvature are proved by using the weak (?-)asymptotic index. As a corollary, the Frankel type theorem is proved.     

Some applications of the KKM-mapping principle in hyperconvex metric spaces

In 1996 Khamsi proved a result in hyperconvex metric spaces which is an analogue of the famous KKM-maps principle proved by Ky Fan in 1972 for topological vector spaces.In this note, using the above result due to Khamsi, we establish two results in hyperconvex metric spaces which are analogues of the famous Ky Fan inequality and Sion minimax theorem proved for topological vector spaces in 1972 and 1958, respectively.     

加法可换可消半环的一个结构定理及应用

半环是一种有很好实际背景和应用前景的代数结构,尤其对于计算机语言的研究有极为重要的作用。因此,对半环的研究越来越引起人们的关注。本文首先证明了每个加法可换可消半环有一个包环,然后在此基础上证明了它们是多重线性等价的,最后证明了加法可消的交换半坏上的Levitzki-Amitsur定理。     

On the matrix Fourier filtering problem for a class of models of nonlinear optical systems with a feedback

A novel statement of the Fourier filtering problem based on the use of matrix Fourier filters instead of conventional multiplier filters is considered. The basic properties of the matrix Fourier filtering for the filters in the Hilbert–Schmidt class are established. It is proved that the solutions with a finite energy to the periodic initial boundary value problem for the quasi-linear functional differential diffusion equation with the matrix Fourier filtering Lipschitz continuously depend on the filter. The problem of optimal matrix Fourier filtering is formulated, and its solvability for various classes of matrix Fourier filters is proved. It is proved that the objective functional is differentiable with respect to the matrix Fourier filter, and the convergence of a version of the gradient projection method is also proved.     

WELL-POSEDNESS OF A PARABOLIC INVERSE PROBLEM

1.IntroductionItiswellknownthatinverseproblemsinpartialdifferentialequations,mostofwhichhavenotyetbeensolveduptonow,remainasachallengeinappliedmathematics.Therefore,manymathematiciansstudiedvariousinverseproblemsforparabolicequa-tions.FOrasimplesurveywereferto[1,2,8,9]foridentifyingcoefficients,[7]foridentifyingboundaryvalues,[4,10]foridentifyingsourcetermsofparabolicequations.Wehavenotincludedalotofpapersconcerningthecomputationalmethodsusedforsolvinginverseparabolicproblems.Inthispaperthein…     

Normal forms of families of maps in the Poincaré domain

An analog of Brushlinskaya’s theorem about normal forms of deformations of vector fields in the Poincaré domain is proved; namely, it is proved that for each analytic map whose linear part at a fixed point belongs to the Poincaré domain and has different eigenvalues, the analytic normal form of a deformation of this map is polynomial and contains (in addition to the linear part) only monomials that are resonant for the unperturbed map. A global (with respect to the parameter) version of this theorem is also proved.     

On the asymptotic solutions of the equations of motion of mechanical systems

The existence of solutions of the equations of motion of non-natural mechanical systems of a certain form which tend to a position of equilibrium when the time increases without limit is proved by the methods described in /1, 2/. The corresponding instability theorem is proved.     

On Recognizability of PSU3(q) by the Orders of Maximal Abelian Subgroups

Siberian Mathematical Journal - Li and Chen in 2012 proved that the simple group A1(pn) is uniquely determined by the set of orders of its maximal abelian subgroups. Later the authors proved that...     

一类非牛顿流弱解的扰动

主要研究一类可压缩粘性非牛顿流方程弱解的扰动性质.在已知弱解存在的基础上,证明了选取适当范数时,沿着给定的时间序列,密度和速率的扰动趋于零.     

边界控制下一阶半线性脉冲调宽采样系统的稳态控制

首先证明了一类一阶非线性系统在周期边界控制下存在全局稳定的周期解.同时,用该结论证明了一类一阶非线性脉冲调宽采样系统存在稳态控制.     

On log-convexity for differences of mixed symmetric means

Recently S. Simi? has proved log-convexity for differences of power means. We prove a generalization of his result. Namely, log-convexity for differences of mixed symmetric means is proved.     

On the spread of positively curved Alexandrov spaces

It was proved by F. Wilhelm that Gromov’s filling radius of closed positively curved manifolds with a uniform lower bound on sectional curvature attains the maximum with the round sphere. Recently the author proved that this is also the case for closed finite-dimensional Alexandrov spaces with a positive lower curvature bound. These were proved as a corollary of a comparison theorem for the invariant called spread of those spaces. In this paper, we extend the latter result to infinite-dimensional Alexandrov spaces.     

On the Extension of D-Poset Valued Measures

A variant of Alexandrov theorem is proved stating that a compact, subadditive D-poset valued mapping is continuous. Then the measure extension theorem is proved for MV-algebra valued measures.     

On the closeness of eigenvalues and singular values for almost normal matrices

It is proved that a matrix is almost normal if and only if its singular values are close to the absolute values of its eigenvalues. In the special case when the spectral norm and spectral radius are close, it is proved that the dominating eigenvalue is well conditioned. A refinement of a perturbation theorem by Henrici is proved, and its numerical behavior is compared with adaptations of the Gerschgorin theorem. It is specially devised for almost triangular matrices.     

Generalized matrix version of reverse Hölder inequality

A generalized matrix version of reverse Cauchy-Schwarz/Hölder inequality is proved. This includes the recent results proved by Bourin, Fujii, Lee, Niezgoda and Seo.     

Dissections of polygons into triangles of equal areas

In 1970 Monsky proved that a square cannot be cut into an odd number of triangles of equal areas. In 1990 it was proved that the statement is true for any centrally symmetric polygon. In the present paper we consider dissections of general polygons into triangles of equal areas.