Riesz Bases and Multiresolution Analyses

Recently we found a family of nearly orthonormal affine Riesz bases of compact support and arbitrary degrees of smoothness, obtained by perturbing the one-dimensional Haar mother wavelet using B-splines. The mother wavelets thus obtained are symmetric and given in closed form, features which are generally lacking in the orthogonal case. We also showed that for an important subfamily the wavelet coefficients can be calculated in O(n) steps, just as for orthogonal wavelets. It was conjectured by Aldroubi, and independently by the author, that these bases cannot be obtained by a multiresolution analysis. Here we prove this conjecture. The work is divided into four sections. The first section is introductory. The main feature of the second is simple necessary and sufficient conditions for an affine Riesz basis to be generated by a multiresolution analysis, valid for a large class of mother wavelets. In the third section we apply the results of the second section to several examples. In the last section we show that our bases cannot be obtained by a multiresolution analysis.     

Symmetries in Projective Multiresolution Analyses

We give an equivariant version of Packer and Rieffel’s theorem on sufficient conditions for the existence of orthonormal wavelets in projective multiresolution analysis. Suppose that the scaling functions are invariant with respect to some finite group action. We give sufficient conditions for the existence of wavelets with similar invariance. Research supported in part by the Research Council of Norway, project number NFR 154077/420. Some of the final work was also done with the support from the project NFR 170620/V30.     

Multiresolution Analysis by Spherical Up Functions

A new class of locally supported radial basis functions on the (unit) sphere is introduced by forming an infinite number of convolutions of "isotropic finite elements." The resulting up functions show useful properties: They are locally supported and are infinitely often differentiable. The main properties of these kernels are studied in detail. In particular, the development of a multiresolution analysis is given based on locally supported zonal functions within the reference space of square-integrable functions over the sphere.     

多个尺度函数产生的多分辨率分析

本文考虑一般细分方程ψｉ（ｘ）＝Σ１≤ｊ≤ＮΣｋ∈Ｚｃｉｊ（ｋ）ψｊ（２ｘ－ｋ），解的存在性，正则性和稳定性，及｛ψｉ｝１≤ｉ≤Ｎ产生Ｌ＾ｐ多分辨率分析的条件。     

Construction of Separately Continuous Functions with Given Restriction

We solve the problem of the construction of separately continuous functions on a product of two topological spaces with given restriction. It is shown, in particular, that, for an arbitrary topological space X and a function g: X R of the first Baire class, there exists a separately continuous function f: X × X R such that f(x, x) = g(x) for every x X.     

Growth of Entire Functions with Given Zeros and Representation of Meromorphic Functions

Mathematical Notes - Let $\Lambda = \{ \lambda n\}$ be a sequence of points on the complex plane, and let $\Lambda (r)$ be the number of points of the sequence $\Lambda$ in the disk $\{...     

与给定多边形相切的可调广义Ball闭曲线

讨论了与给定控制多边形相切的分段三次、五次和六次可调广义Ball曲线的构造方法,所构造的曲线分别是C1,C2和C3连续的,而且对切线多边形是保形的.曲线上的所有广义Ball曲线段的控制点由切线多边形的顶点直接计算产生.给出了在保持公共连接点处相应连续的情况下,内控制点的活动范围.曲线可以在一定范围内做局部修改.计算实例...     

Calculating the Number of Functions with a Given Endomorphism

An iterative procedure is proposed for calculating the number of k-valued functions of n variables such that each one has an endomorphism different from any constant and permutation. Based on this procedure, formulas are found for the number of three-valued functions of n variables such that each one has nontrivial endomorphisms. For any arbitrary semigroup of endomorphisms, the power is found of the set of all three-valued functions of n variables such that each one has endomorphisms from a specified semigroup.     

N维M进制广义多尺度分析及其应用

In this paper,we extend the generalized multiresolution analysis(GMRA)to higher dimensional spaces.The GMRA is generalized from each ladder spaceexpanded by a different scaling function with positive integer dilation factor m≥2.The n-d GMRA is discussed in orthogonal and bi-orthogonal cases.Then the optimalm-band wavelets are applied in processing the image datasets of the human bodyslices.The efficiency and superiority of the algorithm can be seen from the processingresults.     

广义迹函数

本文引进两类新的广义迹函数,用矩阵理论和有限群的表示论研究它们的性质,给出它们在分块厄米特矩阵上的应用.     

Generalized Affine Functions and Generalized Differentials

We study some classes of generalized affine functions, using a generalized differential. We study some properties and characterizations of these classes and we devise some characterizations of solution sets of optimization problems involving such functions or functions of related classes.     

Generalized Bessel Functions for p-Radial Functions

Suppose that and p > 0. In this paper we study the generalized Bessel functions for the surface , introduced by D.St.P. Richards. We derive a recurrence relation for these functions and utilize a series representation to relate them to the classical symmetric functions. These generalized Bessel functions are symmetric with respect to the action of the hyperoctahedral group W_d, which is the symmetry group of the unit sphere. By means of this symmetry under W_d, we further express these generalized Bessel functions in terms of Bessel functions for certain finite reflection groups. For the case in which p = 2, our representations lead to known relations for the classical Bessel functions of order (d - 2)/2. For the case in which p = 1, the generalized Bessel functions have been studied by Berens and Xu in the analysis of summability problems for 1-radial functions, and we show how their results may be framed within our more general context.     

Generalized Connected Functions with Respect to Cones

In this paper, generalized connected functions with respect to cones such as quasi cone-connected, pseudo cone-connected, strongly pseudo cone-connected, and strictly pseudo cone-connected functions are introduced; necessary and sufficient optimality conditions are obtained for a weak minimum, a minimum, and a strong minimum of a vector-valued minimization problem. A Mond–Weir type dual is associated, and weak and strong duality results are established.     

Singular Functions with Applications to Fractal Dimensions and Generalized Takagi Functions

We study a class of singular functions via a generalized dyadic system and Hausdorff dimensions are calculated for several sets related with these functions. Furthermore, we introduce a class of monotonic type on no-interval and almost everywhere differentiable functions that includes—as an exceptional case—the continuous nowhere differentiable Takagi function (multiplied by 2) among them.     

Third-Order Differential Subordinations for Analytic Functions Associated with Generalized Mittag-Leffler Functions

In this paper, third-order differential subordination results are obtained for analytic functions associated with an operator defined by the normalized form of the generalized Mittag-Leffler functions. Some particular cases involving Mittag-Leffler and hyperbolic functions are also considered.     

Linear Generalized Analytic Functions

Complex-valued continuous functions are approximated using solutions of complex partial differential equations of Vekua type.     

Generalized Pseudo-Butterworth Refinable Functions

In this paper we propose the generalized pseudo-Butterworth refinable functions which involve pseudo-splines of type I and II, Butterworth refinable functions, pseudo-Butterworth refinable functions, and almost all symmetric and causal fractional B-splines. Furthermore, the convergence of cascade algorithms associated with the new masks is proved, and Riesz wavelet bases in L ₂(?) corresponding to the parameters are constructed. The regularity of the generalized pseudo-Butterworth refinable functions is also analyzed by Fourier analysis.