再谈欧氏空间的变换和线性变换

文［３］推广了文［１］～［２］中的全部定理,文［４］又推广了文［３］的全部定理,本文推广了文［４］的全部定理,指出了文［４］中的一个错误论断,并给出了线性变换的一个等价条件．为简便,文中的Ｖ表示欧氏空间,ＶＶ表示Ｖ的所有变换的集合,Ｌ（Ｖ）表示Ｖ的所...     

I.J.Matrix定理的更广泛推广

Ｉ．Ｊ．Ｍａｔｒｉｘ定理的更广泛推广张之正（河南洛阳师专数学系４７１０２２）近年来，数学通报连续讨论了１．Ｊ．Ｍａｔｒｉｘ定理的一些推广及其应用（文［ｌ］，［２］用复交函数中的留数定理，文［３Ｊ用初等方法，文［４］用线性代数中的Ｖａｎｄｅｒｍｏｎｄｅ...     

谈欧氏空间中的变换和线性变换

谈欧氏空间中的变换和线性变换彭明海彭学梅（湖南省吉首大学４１６０００）文［３］推广了文［１］、文［２］的全部定理，本文不仅推广了文［３］的全部定理，而且得出新的结果．同时，论证也较简捷．今介绍给同行参考．定理１σ和τ是欧氏空间Ｖ的两个变换，φ是Ｖ的线...     

广义蝴蝶定理的进一步拓广

广义蝴蝶定理的进一步拓广四川蓬溪中学田文宇在《数学通讯》１９９４年第４期上刊登了朱履乾同志的《广义蝴蝶定理》一文（简称文［１］），笔者对文［１］中所述广义蝴蝶定理作进一步拓广．定理设ｃ１，ｃ２，ｃ３为三条均过Ｍ、Ｎ、Ｔ、Ｓ四点的二次曲线，它们顺次与有...     

作为一般性反例的Hamilton图

文［２］对文［１］中的定理３，就ｐ＝２的特殊情况给一个反例．本文则对ｐ〉３的一般情况给出一类反例     

也谈对数大小的比较

也谈对数大小的比较万兴灿（湖北省宜昌市第一中学４４３０００）探究文［１］、［２］、［３］获益非浅，对比言之，文［３］方法从形式到实质仍是文［２］的方法．本文倾向文［１］处理方法，加以推广，则可较全面、简捷地解决对数大小的比较．定理１设１＜ａ＜ｂ，ｍ＞...     

Vandermonde行列式的一个推广及其在初等数学中的应用

Ｖａｎｄｅｒｍｏｎｄｅ行列式的一个推广及其在初等数学中的应用肖振纲（湖南岳阳师专４１４０００）文［１］，［２］先后利用复变函数中的留数定理讨论了初等数学中的Ｉ．Ｊ．Ｍａｔｒｉｘ定理的两个推广，文［３］则用初等方法讨论了所述两个推广的关系，本文首先给出...     

一类非线性多重调和方程△~mu=f(|x|,u,|u|)的正整解

本文建立了一类Ｒｎ（ｎ≥３）中非线性多重调和方程△~ｍｕ＝ｆ（|ｘ|，ｕ，|(ｕ|）（ｍ≥２）正 的径向对称整体解的存在性定理，并给出了解的有关性质，推广了文［１］－［４］的有关结果．     

Banach空间中多值映象的不动点定理

本文中我们首先证明了一个不动点定理，同时从压缩及弱内向两个方向推广了压缩弱内向映象的不动点定理［１，２］．在后两节中讨论了Ｂａｎａｃｈ空间中无界闭子集上的不动点定理，所得结果推广了［３，４］中相应定理．     

关于四元数体上自共轭矩阵的行列式和迹的几个定理

本文采用分析和代数的方法得到了四元数体上自共轭矩阵的行列式和迹的几个定理，推广和改进了文［３］，文［５］相类定理的结果。     

PROPERTIES OF CHARACTERISTIC FUNCTIONS AND EXISTENCE OF LIMIT CYCLES OF LIENARD''S EQUATION

In this paper, the author considers Lienard''s equation, studies the properties of so-called characteristic functions and gives three theorems which ensure that the equation has at least one limit cycle. The theorems generlize Filippov''s Theorem which is a repesentative result, Dragilev''s Theorem, Theorem 1 2 of [6], Theorem 9 of [8] and Theorems 1, 2 of [9] respectively.     

單葉函數的係數與開始多項式

<正> 以fk(z)表單位圓內的K次對稱單葉全純函數,亦即fk(z)=z+a_I~((k))z~(k+1)+a_2~((k))z~(2k+1)+…,|z|<1.以S_k表此種函數之全體.特別,書S以代S_1.     

广义双拟变分不等式和广义拟变分不等式解的存在性

本文研究一类抽象广义双拟变分不等式和广义拟变分不等式问题，获得了解的存在性定理，改进推广了相关文献的一些主要结果．     

一类拟线性抛物型方程解的爆破时间的下界

本文巧妙应用广义Sobolev不等式,研究了一类拟线性抛物型方程解的爆破时间的下界,该结果推广了文献[1]中的定理2.1和定理3.1的结论,同样完善了文献[2]中的模型(4.1)的结论.     

关于“华罗庚-王中烈型不等式”一文的注记

指出了［１］的定理２中的一个错误,推广了［１］中定理１给出的华罗庚－王中烈型不等式,避开控制不等式与动态规划模型等专门工具,改用较为初等的平均值不等式证明之,使改正后的［１］中的定理２成其推论     

UNIQUENESS OF MEROMORPHIC FUNCTIONS WHOSE NONLINEAR DIFFERENTIAL POLYNOMIALS SHARE ONE VALUE OR HAVE THE SAME FIXED POINTS IN AN ANGULAR DOMAIN

In this article, we study the uniqueness question of nonconstant meromorphic functions whose nonlinear differential polynomials share 1 or have the same fixed points in an angular domain. The results in this article improve Theorem 1 of Yang and Hua [26], and improve Theorem 1 of Fang and Qiu [6].     

Orderings of higher level on noetherian rings

The noncommutative algebraic geometry has found fruitful applications in quantum geometry. Similar applications are expected to be found for its younger sister the noncommutative real algebraic geometry

One of the basic results in real algebraic geometry is the Positivestellensatz. The original results of Dubois and Risler (see section 3.3 of [13]) have been extended in many directions. We refer to [14], [1], [2], [3] for commutative rings and [9], [4] for associative rings. The aim of this paper is to prove the higher level Posit ivstellensatz for noncommutative Noetherian rings. Our proof depends on the intersection theorem for orderings of higher level on skew fields ([11], Theorem 3.13). The general case of orderings of higher level on associative rings remains open.     

Approximation of signals of class Lip(α, p) by linear operators

Mittal, Rhoades [5], [6], [7] and [8] and Mittal et al. [9] and [10] have initiated a study of error estimates E_n(f) through trigonometric-Fourier approximation (tfa) for the situations in which the summability matrix T does not have monotone rows. In this paper we continue the work. Here we extend two theorems of Leindler [4], where he has weakened the conditions on {p_n} given by Chandra [2], to more general classes of triangular matrix methods. Our Theorem also partially generalizes Theorem 4 of Mittal et al. [11] by dropping the monotonicity on the elements of matrix rows, which in turn generalize the results of Quade [15].     

Thue inequalities with a small number of primitive solutions

Several upper bounds are known for the numbers of primitive solutions (x; y) of the Thue equation (1) j F(x; y) j = m and the more general Thue inequality (3) 0 &lt; j F(x; y) j m. A usual way to derive such an upper bound is to make a distinction between "small" and "large" solutions, according as max( j x j ; j y j ) is smaller or larger than an appropriate explicit constant Y depending on F and m; see e.g. [1], [11], [6] and [2]. As an improvement and generalization of some earlier results we give in Section 1 an upper bound of the form cn for the number of primitive solutions (x; y) of (3) with max( j x j ; j y j )Y0 , wherec 25 is a constant and n denotes the degree of the binary form F involved (cf. Theorem 1). It is important for applications that our lower bound Y0 for the large solutions is much smaller than those in [1], [11], [6] and [4], and is already close to the best possible in terms of m. ByusingTheorem1 we establish in Section 2 similar upper bounds for the total number of primitive solutions of (3), provided that the height or discriminant of F is suficiently large with respect to m (cf. Theorem 2 and its corollaries). These results assert in a quantitative form that, in a certain sense, almost all inequalities of the form (3) have only few primitive solutions. Theorem 2 and its consequences are considerable improvements of the results obtained in this direction in [3], [6], [13] and [4]. The proofs of Theorems 1 and 2 are given in Section 3. In the proofs we use among other things appropriate modifications and refenements of some arguments of [1] and [6].     

On the diophantine equation x 2 + p 2k = y n

Let 2 ≤ p < 100 be a rational prime and consider equation (3) in the title in integer unknowns x, y, n, k with x > 0, y > 1, n ≥ 3 prime, k ≥ 0 and gcd(x, y) = 1. Under the above conditions we give all solutions of the title equation (see the Theorem). We note that if in (3) gcd(x, y) = 1, our Theorem is an extension of several earlier results [15], [27], [2], [3], [5], [23]. Received: 25 April 2008