Linear Differential Elimination for Analytic Functions

This paper provides methods to decide whether a given analytic function of several complex variables is a linear combination of finitely many given analytic functions with coefficients of the following special form: Each one of these coefficients is a composition of an unknown analytic function of less arguments than the function to be expressed, with fixed analytic functions. Methods which compute suitable coefficient functions in the affirmative case are presented as well.     

Plane Curves Which are Quantum Homogeneous Spaces

Algebras and Representation Theory - Let $mathcal {C}$ be a decomposable plane curve over an algebraically closed field k of characteristic 0. That is, $mathcal {C}$ is defined in k2 by an...     

Homogeneous Functions Of Modules Over Local Rings,Ii

In this paper we continue our investigation of the transfer of structural information between a module V over a local ring R and its associated near-ring M _r(V) of homogeneous functions. We consider the structure of the subnear-ring Dist(M_r(V)) of distributive elements of M _r(V) and also determine conditions under which every homogeneous function on V _r is locally an R-endomorphism of V.     

Localization and Catenarity in Iterated Differential Operator Rings

ABSTRACT

Let k be a field, R an associative k-algebra with identity, Δ a finite set of derivations of R, and R[Θ₁, δ₁] ··· [Θ _n , δ _n ] an iterated differential operator k-algebra over R such that δ _j (Θ _i ) ∈ R[Θ₁, δ₁] ··· [Θ _i?1, δ _i?1]; 1 ≤ i < j ≤ n. If R is Noetherian Δ-hypercentral, then every prime ideal P of A is classically localizable. The aim of this article is to show that under some additional hypotheses on the Δ-prime ideals of R, the local ring A _P is regular in the sense of Robert Walker. We use this result to study the catenarity of A and to compute the numbers μ _i of Bass. Let g be a nilpotent Lie algebra of finite dimension n acting on R by derivations and U(g) the enveloping algebra of g. Then the crossed product of R by U(g) is an iterated differential operator k-algebra as above. In this particular case, our results are known if k has characteristic zero.     

Polynomial Rings in Which Delta Operators are Derivations

For each delta operator Q, we define a multiplication of polynomials of K [ x ] that makes Q a derivation in a suitable polynomial ring. We see that such derivation ring is isomorphic to K [x ] with the usual derivative operator D. We supply a complete classification of the isomorphisms between these two structures, ending with a slight generalization.     

On Homogeneous Differential Polynomials of Meromorphic Functions

In this paper, we study one conjecture proposed by W. Bergweiler and show that any transcendental meromorphic functions f(z) have the form exp(αz+β) if f(z)f″(z)–a(f′ (z))²≠0, where . Moreover, an analogous normality criterion is obtained. Supported by National Natural Science Foundation and Science Technology Promotion Foundation of Fujian Province (2003)     

Injective Hulls of Simple Modules over Differential Operator Rings

We study injective hulls of simple modules over differential operator rings R[θ; d], providing necessary conditions under which these modules are locally Artinian. As a consequence, we characterize Ore extensions of S = K[x][θ; σ, d] for σ a K-linear automorphism and d a K-linear σ-derivation of K[x] such that injective hulls of simple S-modules are locally Artinian.     

Reduction of Generalized Resolvents of Linear Operator Functions

For the meromorphic generalized resolvent of a linear operator function a reduction is constructed. The spaces generating this reduction are also determined. Two special cases of this reduction are considered.     

On the Siegel Conjecture for Second-Order Homogeneous Linear Differential Equations

The structure of the set of E-functions satisfying second-order homogeneous linear differential equations with coefficients from $\mathbb{C}(z)$ is described.     

Subordination Results for p-Valent Meromorphic Functions Associated with a Linear Operator

In this paper, by making use of the Hadamard products, we obtain some subordination results for certain family of meromorphic functions defined by using a new linear operator.     

Subordination Results for ρ-Valent Meromorphic Functions Associated with a Linear Operator

In this paper, by making use of the Hadamard products, we obtain some subordination results for certain family of meromorphic functions defined by using a new linear operator.     

有限环上的齐次重量与M(o)bius函数

讨论了有限环上齐次重量、M(o)bius函数和欧拉phi-函数等函数之间的关系.在有限主理想环上给出了这些函数的易于计算的刻画,对于整数剩余类环把它们还原成了经典的数论M(o)bius函数和数论欧拉phi-函数.     

巧学妙用常系数齐次线性微分方程——一道赛题的另一种解法

对一道数学竞赛题,介绍微分方程解法,通过对参数β取值的分类讨论,将原命题等价转化成一阶和二阶常系数齐次线性微分方程的求解问题,能够直观地给出证明.     

On Quasiconvex Functions Which are Convexifiable or Not

Journal of Optimization Theory and Applications - A quasiconvex function f being given, does there exist an increasing and continuous function k which makes $$kcirc f$$ convex? How to build such a...     

Accretivity of the General Second Order Linear Differential Operator

For the general second order linear differential operator ■ with complex-valued distributional coefficients a_(jk), b_j, and c in an open set Ω ? R~n(n ≥ 1), we present conditions which ensure that-L~0 is accretive, i.e., Re-L_0φ, φ ≥ 0 for all φ∈ C_0~∞(Ω).     

由自共轭线性微分算子所确定的函数类在Lq(T)中的相对宽度

得到了使等式Kn(K2(Pr),MK2(Pr),L2(T))=dn(K2(Pr),L2(T))成立的最小M值,并计算了Kn(K2(Pr),K2(Pr),Lq(T))的渐近阶,其中Kn(.,.,Lq(T))和dn(.,Lq(T)),1≤q≤∞,分别代表Kolmogorov意义下在Lq(T)中的相对宽度和宽度,K2(Pr)表示定义在[-π,π]上由自共轭线性微分算子所确定的光滑函数类.     

Rings Over Which Flat Covers of Finitely Generated Modules are Projective

We provide sufficient conditions for the existence and uniqueness of normal forms of sequences of HNN extensions defined by Bokut′. Furthermore, we show that under an assumption, which holds for various applications, such normal forms always exist (but might not be unique). The conditions are amenable to be used in automatic theorem provers. We discuss also how to obtain a Gröbner–Shirshov basis from the rewrite rules of Bokut′ normal forms under certain assumptions. Finally, we provide an application drawn from a paper of Aanderaa and Cohen to illustrate the sufficiency conditions.     

高阶齐次线性微分方程解的零点

研究了一类高阶齐次线性微分方程解的零点收敛指数,并得到当方程的系数A_0为整函数,其泰勒展式为缺项级数,并且A_0起控制作用时,方程f~((k))+A_(k-2)f~((k-2))+…+A_1f′+A_0f=0的任意两个线性无关解f_1,f_2满足max{λ(f_1),λ(f_2)}=∞,其中λ(f)表示亚纯函数.f的零点收敛指数.