On the Positive Definiteness of Certain Functions

For a coinmutative senugoup (S, +, *) with involution and a function f : S → [0, ∞), the set S(f) of those p ≥ 0 such that f^P is a positive definite function on S is a closed subsemigroup of [0, ∞) containing 0. For S = (IR, +, x* = -x) it may happen that S(f) = { kd : k ∈ N₀ } for some d > 0, and it may happen that S(f) = {0} ? [d, ∞) for some d > O. If α > 2 and if S = (?, +, n* = -n) and f(n) = e^?[n]α or S = (IN₀, +, n* = n) and f(n) = e^nα, then S(f) ∪ (0, c) = ? and [d, ∞) ? S(f) for some d ≥; c > 0. Although (with c maximal and d minimal) we have not been able to show c = d in all cases, this equality does hold if S = ? and α ≥ 3.4. In the last section we give sinipler proofs of previously known results concerning the positive definiteness of x → e^?||x||α on normed spaces.     

具有线性约束条件的Hermite型是否正定的一种判别法

具有线性约束条件的Ｈｅｒｍｉｔｅ型是否正定的一种判别法周伟光（南京教育学院数学系，南京２１００１７）在经济数学中，有一个对具有某种线性约束条件的实二次型是否正定的判别法。文「２］对此判别法作了严格的叙述与证明．按文［２］，该判别法叙述如下：＂设Ｈ一】...     

A Note on C-wrpp Semigroups

ＬｅｔＲｄｅｎｏｔｅＧｒｅｅｎ ｓＲ ｒｅｌａｔｉｏｎｏｎａｓｅｍｉｇｒｏｕｐＳ .ＷｅｄｅｆｉｎｅａｒｉｇｈｔｃｏｎｇｒｕｅｎｃｅＬ ｏｎＳｉｎｔｈｅｒｕｌｅ:ｆｏｒａ ,ｂ∈Ｓ ,(ａ ,ｂ) ∈Ｌ ｉｆｆｆｏｒａｌｌｘ ,ｙ∈Ｓ1,　　 (ａｘ ,ａｙ) ∈Ｒ (ｂｘ,ｂｙ) ∈Ｒ .ＡｓｅｍｉｇｒｏｕｐＳｉｓｓａｉｄｔｏｂｅａＣ ｗｒｐｐｓｅｍｉｇｒｏｕｐｉｆａｌｌｉｄｅｍｐｏｔｅｎｔｓｏｆＳａｒｅｃｅｎｔｒａｌｉｎＳａｎｄｅａｃｈＬ ｃｌａｓｓｏｆＳｃｏｎｔａｉｎｓａｎｉｄｅｍｐｏｔｅｎｔ(ｓｅｅ [1 ] ) .　Ｔｈｅｐ…     

半群上条件正定函数的扩张

讨论半群上条件正定函数的扩张问题.得到一个扩张定理.作为应用,得到有界扩张定理和Pontryagin空间上量子力学的一个基本定理.     

Decomposition of Exponential Distributions on Positive Semigroups

Let (S,·) be a positive semigroup and T a sub-semigroup of S. In many natural cases, an element can be factored uniquely as x=yz, where and where z is in an associated “quotient space” S/T. If X has an exponential distribution on S, we show that Y and Z are independent and that Y has an exponential distribution on T. We prove a converse when the sub-semigroup is for . Specifically, we show that if Y _t and Z _t are independent and Y _t has an exponential distribution on S _t for each , then X has an exponential distribution on S. When applied to ([0,∞), +) and , these results unify and extend known results on the quotient and remainder when X is divided by t.     

关于交换序半群的一个注记

给出了正则交换序半群的与素理想结构有关的若干性质，还给出了为有限个主理想的并的交换序半群类中的诺特性，阿基米德性，正则性以及有限生成性之间的一些关系。     

A Note on Feller Semigroups

We present an integral representation of the operators which form a Feller semigroup using a result of P. Courrège.     

Strictly Positive Definite Functions on a Real Inner Product Space

If converges for all with all coefficients , then the function is positive definite on H×H for any inner product space H. Set K={k: a _k >0}. We show that is strictly positive definite if and only if K contains the index 0 plus an infinite number of even integers and an infinite number of odd integers.     

Exchangeable Random Ordered Trees by Positive Definite Functions

We prove that the set of exchangeable random totally ordered trees is a Bauer simplex whose extreme points are the generalized paint-box processes. The method is based on semigroups, analogous to Hirth and Ressel,^{(2, 3)} and is readily also applied to inverse trees.     

对“关于复正定矩阵行列式的不等式”一文的注记

本文指出文 [1 ]中的错误 ,并把文 [1 ]中关于复正定矩阵与正定 Hermite矩阵的行列式不等式推广到较为广泛的复矩阵类     

正定矩阵的性质及相关问题

正定矩阵具有非常广泛的应用.本文对正定矩阵的结论与重要性质进行了归纳总结,并在此基础上,对部分结论与性质进行了适当的推广.     

关于正定矩阵的两个不等式

通过Hermite矩阵的谱分解及一个改进的Young不等式,得到了关于正定矩阵的两个不等式,所得结果是对一些经典的矩阵不等式的进一步推广.最后,作为应用,给出了著名的Holder不等式和Minkowsi不等式的一种反向形式.     

正定Hermite矩阵加权幂平均的行列式不等式

本文给出了m个正定Hermite矩阵加权幂平均的行列式的一个不等式，它是m个正数的加权益平均不等式的自然推广，也是正定Hermite矩阵行列式的凸性不等式的推广．     

关于正定矩阵的几个问题

本文推广了文［１］的主要定理，给出了用低阶矩阵判定高阶矩阵正定的判定定理，同时给出了矩阵方程ＡＸ＝Ｂ的反问题在正定矩阵类中解存在的充要条件及解的一般形式．     

关于正定厄米特矩阵的一个定理

本文推广了文献 [2 ]给出的一个不等式 ,得到以下结果 :设 Ai,Bi,… ,Ci( i=1 ,2 ,… ,k)都是 n阶正定厄米特矩阵 ,α,β,… ,γ都是正实数 ,且 α+β+… +γ=p≥1 ,则∑ki=1|Ai|α|Bi|β… |Ci|γ <∑ki=1Ai α ∑ki=1Bi β… ∑ki=1Ci γ     

关于分段函数定积分的计算

通过例题分别讨论分段连续函数定积分的计算及分段有界非连续函数定积分的计算,旨在于进一步丰富高等数学的教学内容,提高学生的计算能力.     

Positive definite spherical functions on Olshanskii domains

Let be a simply connected complex Lie group with Lie algebra , a real form of , and the analytic subgroup of corresponding to . The symmetric space together with a -invariant partial order is referred to as an Olshanskii space. In a previous paper we constructed a family of integral spherical functions on the positive domain of . In this paper we determine all of those spherical functions on which are positive definite in a certain sense.

     

关于0-F-逆半群的一个注记

In this paper, we introduce 0-F-inverse semigroups and characterize 0-F-inverse categorical semigroups by using their minimal primitive congruenceβ.     

关于余弦算子函数的一个结果

设Ａ是Ｂａｎａｃｈ空间Ｘ中的闭线性算子,对凡　是单射。文中定义了Ｂａｎａｃｈ空间　范数　强于Ｘ的范数。我们证明了算子Ａ在空间Ｚ中的部分ＡＺ生成Ｚ中的一个余弦算子函数,空间Ｚ具有某种意义上的极大性。