傅立叶变换与小波变换的比较教学

本文针对小波变换教学中小流变换概念理解困难的问题，提出了一种比较教学方法，通过分析小波变换与傅立叶变换之间的联系，并从四个方面进行对比，清楚地描述了小波变换的本质，从而对加深对小波变换的理解。     

关于广义Volterra拉普拉斯与傅立叶变换的关系

本是献[1]工作的继续，研究了广义Volterra拉普拉斯的性质及其与傅立叶变换的关系并进行了研讨．     

周期函数和非平稳周期函数的小波变换

探讨了三角函数、周期函数以及一类非平稳周期函数小波变换的一些性质,发现周期函数的小波能谱的峰高和峰宽均正比于信号的周期.提出了一个新的只利用与信号周期有关的一个尺度小波变换系数的重构公式,它可准确地重构三角函数,对一般周期函数的重构结果优于其Fourier级数中的任何一项,对一类均值和振幅变化的非平稳周期函数的重构结果与信号非常吻合.     

基于傅立叶变换的SVJ模型的欧式期权定价

为了更加精确的计算期权价格,将结合随机波动和跳扩散模型(以下简称SVJ模型)以更好的描述期权标的资产价格过程,然而这样的价格过程无法得到概率密度函数的封闭形式,而只能得到包含特殊函数和无限求和的复杂的表达式.不过它们的特征函数都是封闭且是唯一的,因而可以通过它们的特征函数,并运用两种傅立叶变换的方法来求出期权价格.其中FFT算法计算的结果将与Monte Carlo模拟得出的结果进行比较,然后再将SVJ模型的计算结果和Black-Scholes模型进行比较.     

半群上的非交换调和分析

设Ａ（Ｍ）是 Ｃ＊－代数（ｖｏｎ Ｎｅｕｍａｎｎ代数）．本文证明了，若φ是定义在Ｒ＋上取值于Ａ（Ｍ）的范数连续的有界正定函数，则φ可表示为Ｒ＋上取值于Ａ＇＇（Ｍ）的有界半变差向量测度的Ｌａｐｌａｃｅ变换．同时也证明了取值于Ａ（Ｍ）的Ｈａｍｂｕｒｇｅｒ型的矩量问题．     

双代数余循环的余同调变换

在［８］中,作者讨论余循环交叉积和扭积之间的关系（见定理 ５．３）．设 Ａ＃ＸＨ为余循环交叉积,ｒ∈Ｈｏｍ（Ｈ,Ａ）,是卷积可逆的,且ｒ（１）＝１．在］［６］中,Ｓ．Ｍａｊｉｄ对任意地余循环Ｘ定义了余同调变换 ｘｒ·在本文中,首先证明了［８］中的定理 ５．３以及它的对偶在一般情况下成立． Ｓ． Ｍａｊｉｄ在［５］中给出了余循环交叉积和余循环交叉余积形成双代数的充要条件,这种结构称为Ｂｉｃｒｏｓｓｐｒｏｄｕｃｔ积．这里讨论了余循环余同调变换如何具体地保持这种双代数结构．     

双代数余循环的余同调变换

在[8]中,作者讨论余循环交叉积和扭积之间的关系(见定理5.3).设A#xH为余循环交叉积,γ∈Hom(H,A)是卷积可逆的,且γ(1)=1.在[6]中,s.Majid对任意地余循环x定义了余同调变换xγ.在本文中,首先证明了[8]中的定理5.3以及它的对偶在一般情况下成立.s.Majid在[5]中给出了余循环交叉积和余循环交叉余积形成双代数的充要条件,这种结构称为Bicrossproduct积.这里讨论了余循环余同调变换如何具体地保持这种双代数结构.     

积分变换中常见问题

积分变换是工科基础课程,具有公式多、难度大、应用广泛的特点.本文对积分变换中教师和学生易忽略问题进行了归纳总结,并举出大量例子.     

线性代数变换与仿射几何变换

本文介绍线性代数中的二维代数变换与解析几何中的平面仿射变换的关系,代数变换及其变换矩阵的几何意义,各种仿射变换的矩阵表示及其矩阵性质,梳理仿射变换下的不变性质与不变量.     

Projections onto invariant subspaces of some banach algebras

In this paper, among other things, the author studies the weak^＊-closed left translation invariant complemented subspace of semigroup algebras and group algebras. Also, the author studies the relationships between projections and amenability.     

Intermediate subfactors with no extra structure

If are type II factors with and we show that restrictions on the standard invariants of the elementary inclusions , , and imply drastic restrictions on the indices and angles between the subfactors. In particular we show that if these standard invariants are trivial and the conditional expectations onto and do not commute, then is or . In the former case is the fixed point algebra for an outer action of on and the angle is , and in the latter case the angle is and an example may be found in the GHJ subfactor family. The techniques of proof rely heavily on planar algebras.

     

由一元连续小波变换得到的二元连续小波变换及重构公式

讨论了L2(R2)空间中连续小波变换,分别得到由一元变换函数构造二元变换函数的二元小波变换及重构公式,得到重构公式在L2(R2)中范数收敛意义下成立的条件.     

Exchange Relation Planar Algebras

An inclusion of II ₁ factors NM of finite index has as an invariant, a double sequence of finite-dimensional algebras known as the standard invariant. Planar algebras were introduced by V. Jones as a geometric tool for computing standard invariants of existing subfactors as well as generating standard invariants for new subfactors. In this paper we define a class of planar algebras, termed exchange relation planar algebras, that provides a general framework for understanding several classes of known subfactor inclusions: the Fuss–Catalan algebras (i.e. those coming from the presence of intermediate subfactors) and all depth 2 subfactors. In addition, we present a new class of planar algebras (and thus a new class of subfactors) coming from automorphism subgroups of finite groups.     

Planar algebra of the subgroup-subfactor

We give an identification between the planar algebra of the subgroupsubfactor R ⋊ H ⊂ R ⋊ G and the G-invariant planar subalgebra of the planar algebra of the bipartite graph ★ _n , where n = [G: H]. The crucial step in this identification is an exhibition of a model for the basic construction tower, and thereafter of the standard invariant of R ⋊ H ⊂ R ⋊ G in terms of operator matrices. We also obtain an identification between the planar algebra of the fixed algebra subfactor R ^G ⊂ R ^H and the G-invariant planar subalgebra of the planar algebra of the ‘flip’ of ★ _n .     

Quaternion Fourier and linear canonical inversion theorems

The quaternion Fourier transform (QFT) is one of the key tools in studying color image processing. Indeed, a deep understanding of the QFT has created the color images to be transformed as whole, rather than as color separated component. In addition, understanding the QFT paves the way for understanding other integral transform, such as the quaternion fractional Fourier transform, quaternion linear canonical transform, and quaternion Wigner–Ville distribution. The aim of this paper is twofold: first to provide some of the theoretical background regarding the quaternion bound variation function. We then apply it to derive the quaternion Fourier and linear canonical inversion formulas. Secondly, to provide some in tuition for how the quaternion Fourier and linear canonical inversion theorems work on the absolutely integrable function space. Copyright © 2016 John Wiley & Sons, Ltd.     

推广约当引理以及Laplace变换与Fourier变换的对应关系

单变量复变函数积分中用到的约当引理是在lim||f（Reiφ）||＝0（0≤≤π）的条件下使用的，而实际上约当引理可以在比较宽松的条件下就可使用，被积函数f（z）除在z的上半平面（Ⅰmz≥0）有有限个孤立奇点外，处处解析，且对p＞0只要，则这里z＝Rei，CR为上半平面的开弧半圆围道，利用推广约当引理可以证明Laplace变换实际上是对应的其复变量函数的Fourier变换。     

Fourier Transform Over Local Fields

The Fourier transform in the space of distributions on finite-dimensional vector spaces over local fields is defined, and a strong similarity between the case of archimedian and non-archimedian fields is discussed. Furthermore, the definition of the Fourier transform for the case of “functions” on finite-dimensional vector spaces over 2-dimensional local fields is introduced. Leonardo da Vinci lecture held on June 29, 2005 Received: October 2005     

Forked Temperley-Lieb algebras and intermediate subfactors

We consider noncommuting pairs P, Q of intermediate subfactors of an irreducible, finite-index inclusion N⊂M of II₁ factors such that P and Q are supertransitive with Jones index less than 4 over N. We show that up to isomorphism of the standard invariant, there is a unique such pair corresponding to each even value but none for the odd values . We also classify the angle values which occur between pairs of intermediate subfactors with small index over their intersection: if [P:N],[Q:N]<4, then the unique nontrivial angle value is always .