关于SL(2,R)上速降函数的反演公式

在局部紧可分群的一般理论中，分解正则表示以及获得反演公式（或 Ｐｌａｎ－ｃｈｅｒｅｌ定理的明确表示）是调和分析的基本目标之一．ＳＬ（２，　）是最简单的非交换局部紧么模半单Ｌｉｅ群．Ｈａｒｉｓｈ－Ｃｈａｎｄｒａ在 Ｃ∞ｃ（ＳＬ（２，　））上获得了反演公式，Ｘｉａｏ和ｈｅｎｇ在文［１］中证明了Ｃ３ｃ（ＳＬ（２， ）上的反演公式．在文［２］中Ｚｈｅｎｇ引入了Ｌｉｅ群Ｇ上函数的广义微分（Ａ导数）概念．在本文中，我们利用文［２］中的微分概念来研究ＳＬ（２，　）上可微函数的Ｆｏｕｒｉｅｒ变换的阶，并获得了ＳＬ（２，　）上速降函数的反演公式．     

三维Ⅱ型剖分上的样条空间

三维Ⅱ型剖分上的样条空间施锡泉（大连理工大学数学研究所）ＳＰＬＩＮＥＳＰＡＣＥＳＯＮＴＹＰＥ－２ＴＲＩＡＮＧＵＬＡＴＩＯＮＩＮＲ￣３￥ＳｈｉＸｉ－ｑｕａｎ（Ｉｎｓｔ．ｏｆＭａｔｈ．，ＤａｌｉｎＵｎｉｖ．ｏｆＳｃｉ．ａｎｄＴｅｃｈ．）Ａｂｓｔｒａｃｔ：...     

多元Bernstein-Durrmeyer算子L~p逼近的Steckin-Marchaud型不等式

本文给出多元 Ｂｅｒｎｓｔｅｉｎ－Ｄｕｒｒｍｅyｅｒ算子 ＬＰ逼近的 Ｓｔｅｃｋｉｎ－Ｍａｒｃｈａｕｄ型不等式,从该不等式得到多元Ｂernstein-Ｄurrmeyer算子Ｌp对逼近的特征刻划定理．     

非线性Lipschitz算子的Lipschitz对偶算子及其应用

在文山中我们对非线性Ｌｉｐｓｃｈｉｔｚ算子定义了其Ｌｉｐｓｃｈｉｔｚ对偶算子，并证明了任意非线性Ｌｉｐｓｃｈｉｔｚ算子的Ｌｉｐｓｃｈｉｔｚ对偶算子是一个定义在Ｌｉｐｓｃｈｉｔｚ对偶空间上的有界线性算子．本文还进一步证明：设Ｃ为 Ｂａｎａｃｈ空间 Ｘ的闭子集，Ｃ＊Ｌ为Ｃ的 Ｌｉｐｓｃｈｉｔｚ对偶空间，Ｕ为 Ｃ＊Ｌ上的有界线性算子，则当且仅当 Ｕ为 ｗ＊－ｗ＊连续的同态变换时，存在Ｌｉｐｓｃｈｉｔｚ连续算子Ｔ，使Ｕ为Ｔ的Ｌｉｐｓｃｈｉｔｚ对偶算子．这一结论的理论意义在于：它表明一个非线性Ｌｉｐｓｃｈｉｔｚ算子的可逆性问题可转化为有界线性算子的可逆性问题．作为应用，通过引入一个新概念──ＰＸ－对偶算子，在一般框架下给出了非线性算子半群的生成定理．     

关于苏联科学院数学研究所在函数逼近论方面的工作（下）

关于苏联科学院数学研究所在函数逼近论方面的工作（下）ＣＡ．捷里亚可夫斯基（原苏联科学院数学研究所）６多元函数逼近多元函数逼近的正逆定理最早是由Ｄ．Ｊａｃｋｓｏｎ［４］和Ｓ．Ｎ．Ｂｅｒｎｓｔｅｉｎ［５］与一元函数的定理同时给出的，对多元函数的系统研究要...     

STABILITY OF GLOBAL GEVREY SOLUTION TO WEAKLY HYPERBOLIC EQUATIONS

ＳＴＡＢＩＬＩＴＹＯＦＧＬＯＢＡＬＧＥＶＲＥＹＳＯＬＵＴＩＯＮＴＯＷＥＡＫＬＹＨＹＰＥＲＢＯＬＩＣＥＱＵＡＴＩＯＮＳＭ．ＲＥＩＳＳＩＧＫ．ＹＡＧＤＪＩＡＮＭａｎｕｓｃｒｉｐｔｒｅｃｅｉｖｅｄＮｏｖｅｍｂｅｒ１４，１９９４．ＦａｃｕｌｔｙｏｆＭ...     

T样条函数空间的局部支集基

Schumaker，L.L.在其名著《Spline Function；Basic Theory》中第九章给出了Tchebysheff样条函数空间的局部支集基定理，可惜其证明却是错的，本文给出了上述定理的正确证明。     

LOCAL AND GLOBAL EXPOSED POINTS

ＬＯＣＡＬＡＮＤＧＬＯＢＡＬＥＸＰＯＳＥＤＰＯＩＮＴＳＭ．Ｂｅｌｔａｇｙ（ＭａｔｈｅｍａｔｉｃｓＤｅｐａｒｔｍｅｎｔ，ＦａｃｕｌｔｙｏｆＳｃｉｅｎｃｅＴａｎｔａＵｎｉｖｅｒｓｉｔｙ，Ｅｇｙｐｔ．）Ａｂｓｔｒａｃｔ：Ｉｎｔｈｉｓｐａｐｅｒｗｅｄｅｒｉｖ...     

CONDITIONED SUPERPROCESSES

ＣＯＮＤＩＴＩＯＮＥＤＳＵＰＥＲＰＲＯＣＥＳＳＥＳＬＩＣＵＮＨＡＮＧＷＵＲＯＮＧＡｂｓｔｒａｃｔＡｃｌａｓｓｏｆｓｕｐｅｒｐｒｏｃｅｓｅｓｗｈｉｃｈｄｉｅｓｏｕｔｉｓｉｎｖｅｓｔｉｇａｔｅｄ．Ｕｎｄｅｒｔｈｅｃｏｎｄｉｔｉｏｎｏｆｎｏｒｅｘｔｉ...     

GOPPA CODES FROMARTIN-SCHREIER FUNCTION FIELDS

ＧＯＰＰＡＣＯＤＥＳＦＲＯＭＡＲＴＩＮ－ＳＣＨＲＥＩＥＲＦＵＮＣＴＩＯＮＦＩＥＬＤＳ￥ＨＡＮＷＥＮＢＡＯ（ＤｅｐａｔｍｅｌｌｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＳｉｃｈｕａｎＵｎｉｖｅｒｓｉｔｙｔＣｈｅｎｇｄｕ６１００６４，Ｓｉｃｈｕａｎ，Ｃｈｉｎａ．）Ａ...     

New spline basis functions for sampling approximations

We describe a method of constructing a new kind of splines with compact support on . These basis functions consisting of a linear combination of the cardinal B-splines of mixed orders enable us to achieve simultaneously a good sampling approximation and an interpolation of any smooth function.     

The Structural Characterization and Locally Supported Bases for Bivariate Super Splines

Super splines are bivariate splines defined on triangulations, where the smoothness enforced at the vertices is larger than the smoothness enforced across the edges. In this paper, the smoothness conditions and conformality conditions for super splines are presented. Three locally supported super splines on type-1 triangulation are presented. Moreover, the criteria to select local bases is also givenBy using local supported super spline function, a variation-diminishing operator is built. The approximation properties of the operator are also presented.     

Local Sampling and Reconstruction in Shift-Invariant Spaces and Their Applications in Spline Subspaces

The local reconstruction from samples is one of the most desirable properties for many applications in signal processing. Local sampling is practically useful since we need only to consider a signal on a bounded interval and computer can only process finite samples. However, the local sampling and reconstruction problem has not been given as much attention. Most of known results concern global sampling and reconstruction. There are only a few results about local sampling and reconstruction in spline subspaces. In this article, we study local sampling and reconstruction in general shift-invariant spaces and multiple generated shift-invariant spaces with compactly supported generators. Then we give several applications in spline subspaces and multiple generated spline subspaces.     

多元弱样条空间和最小确定集

根据研究多元弱样条函数的B—网方法,给出了某些多元弱样条函数空间的最小确定集的构造方法,并从而求出了它们的维数．本文还讨论了对偶基的局部支集性质。     

Weak descartes systems in generalized spline spaces

A class of generalized spline spaces is introduced for which a basis of functions with local support is constructed by using a recursion relation. It is shown that this basis forms a weak Descartes system. Moreover, an interpolation property is given.     

Local Properties of Cardinal Interpolatory Function

In [1], a kind of periodic cardinal interpolatory function (PCIF) is constructed, and they also use it to construct periodic wavelets. But the localization of PCIF is not known yet. In this paper, we study the local property of PCIF using two different methods. The results show that PCIF has very good localization. Some new properties of Bernoulli spline are also introduced. The first author is supported partially by NFSC Grant The second author supported by LAPC Grant. Current address: Nadec, Institute of Automation, Academia Sinica, Beijing, 100080, China     

Spline Approximation Methods with Uniform Meshes in Algebras of Multiplication and Convolution Operators

The purpose of this paper is to obtain necessary and sufficient conditions for maximum defect spline approximation methods with uniform meshes to be stable. The methods are applied to operators belonging to the closed subalgebra of ℒ︁ (L² (ℝ)) generated by operators of multiplication by piecewise continuous functions on ℝ and convolution operators also with piecewise continuousgenerating functions. To that purpose, a C*-algebra of sequences is introduced, which contains the special sequences of approximating operators we are interested in. There is a direct relationship between the applicability of the approximation method to a given operator and invertibility of the corresponding sequence in this C*-algebra. Exploring this relationship, applicability criteria are derived by the use of C*-algebra and Banach algebra techniques (essentialization, localization andidentification of the local algebras by means of construction of locally equivalent representations). Finally, examples are presented, including explicit conditions for the applicability of spline Galerkin methods to Wiener-Hopf operators with piecewise continuous symbols.     

多元指数磨光算子的构造和相关偏微分方程基本解与磨光核的升维解法

本文目的在于回答:δ分布的多元指数磨光函数,即磨光核函数的解析表示问题.从我们给出的多元指数磨光算子的定义出发,将磨光核函数的表示,归结为先求相应偏微分方程的基本解,再对它的广义差分.然后用我们提出的"升维方法",彻底解决了基本解的解析表达问题.从而也就回答了磨光核函数的解析表示.磨光核函数的支集既可以是高维立方体,也可以是高维单纯形.因此,多元指数箱(E-Box)和单纯形(E-Simplex)样条的表示,皆能用我们的统一方法解决.     

Near-Best Univariate Spline Discrete Quasi-Interpolants on Nonuniform Partitions

The univariate spline quasi-interpolants (QIs) studied in this paper are approximation operators using B-spline expansions with coefficients that are linear combinations of discrete values of the function to be approximated. When working with nonuniform partitions, the main challenge is to find QIs that have both good approximation orders and uniform norms which are bounded independently of the given partition. Near-best QIs are obtained by minimizing an upper bound for the infinity norm of QIs depending on a certain number of free parameters, thus reducing this norm. This paper is devoted to the study of some families of near-best discrete quasi-interpolants (dQIs) of approximation order 3.      

Accelerated Failure Time Model for Arbitrarily Censored Data With Smoothed Error Distribution

This article develops a semiparametric procedure to estimate parameters of an accelerated failure time model. To express the density of the error distribution, we use the P-spline (B-splines with penalties) smoothing technique. To accommodate error densities with infinite support (and for other reasons) we replace the B-splines with their limits as the degree of the B-spline goes to infinity; namely, with normal densities. The spline coefficients as well as any number of regression parameters are quickly and accurately estimated via penalized maximum likelihood. The method directly provides predictive survival distributions for fixed values of covariates while allowing for left-, right-, and interval-censored data. The approach has been implemented as an R package and is applied here to the problem of predicting AIDS-free survival in the presence of interval censoring.