Classical wavelet systems over finite fields
Pages 1-18
https://doi.org/10.22072/wala.2016.23236
Arash Ghaani Farashahi
Abstract This article presents an analytic approach to study admissibility conditions related to classical full wavelet systems over finite fields using tools from computational harmonic analysis and theoretical linear algebra. It is shown that for a large class of non-zero window signals (wavelets), the generated classical full wavelet systems constitute a frame whose canonical dual are classical full wavelet frames as well, and hence each vector defined over a finite field can be represented as a finite coherent sum of classical wavelet coefficients as well.
Linear combinations of wave packet frames for L^2(R^d)
Pages 19-32
https://doi.org/10.22072/wala.2016.23237
Ashok Kumar Sah
Abstract In this paper we study necessary and sufficient conditions for some types of linear combinations of wave packet frames to be a frame for L2(Rd). Further, we illustrate our results with some examples and applications.
Cartesian decomposition of matrices and some norm inequalities
Pages 33-42
https://doi.org/10.22072/wala.2016.23238
Alemeh Sheikhhosseini, Golamreza Aghamollaei
Abstract Let X be an n-square complex matrix with the Cartesian decomposition X = A + i B, where A and B are n times n Hermitian matrices. It is known that $Vert X Vert_p^2 leq 2(Vert A Vert_p^2 + Vert B Vert_p^2)$, where $p geq 2$ and $Vert . Vert_p$ is the Schatten p-norm. In this paper, this inequality and some of its improvements are studied and investigated for the joint C-numerical radius, joint spectral radius, and for the C-spectral norm of matrices.
Pseudoframe multiresolution structure on abelian locally compact groups
Pages 43-54
https://doi.org/10.22072/wala.2016.23239
Hamide Azarmi, Radjabali Kamyabi Gol, Mohammad Janfada
Abstract Let $G$ be a locally compact abelian group. The concept of a generalized multiresolution structure (GMS) in $L^2(G)$ is discussed which is a generalization of GMS in $L^2(mathbb{R})$. Basically a GMS in $L^2(G)$ consists of an increasing sequence of closed subspaces of $L^2(G)$ and a pseudoframe of translation type at each level. Also, the construction of affine frames for $L^2(G)$ based on a GMS is presented.
Quartic and pantic B-spline operational matrix of fractional integration
Pages 55-68
https://doi.org/10.22072/wala.2016.23240
Ataollah Askari Hemmat, Tahereh Ismaeelpour, Habibollah Saeedi
Abstract In this work, we proposed an effective method based on cubic and pantic B-spline scaling functions to solve partial differential equations of fractional order. Our method is based on dual functions of B-spline scaling functions. We derived the operational matrix of fractional integration of cubic and pantic B-spline scaling functions and used them to transform the mentioned equations to a system of algebraic equations. Some examples are presented to show the applicability and effectivity of the technique.
Triangularization over finite-dimensional division rings using the reduced trace
Pages 69-74
https://doi.org/10.22072/wala.2016.23241
Hossein Momenaee Kermani
Abstract In this paper we study triangularization of collections of matrices whose entries come from a finite-dimensional division ring. First, we give a generalization of Guralnick's theorem to the case of finite-dimensional division rings and then we show that in this case the reduced trace function is a suitable alternative for trace function by presenting two triangularization results. The first one is a generalization of a result due to Kaplansky and in the second one a triangularizability condition which is dependent on a single element is presented.