N-strongly quasi-invariant measure on double coset spaces
Volume 9, Issue 1, 2022, Pages 67-84
https://doi.org/10.22072/wala.2022.550186.1370
Fatemeh Fahimian, Rajab Ali Kamyabi Gol, Fatemeh Esmaeelzadeh
Abstract Let $G$ be a locally compact group, $H$ and $K$ be two closed subgroups of $G$, and $N$ be the normalizer group of $K$ in $G$. In this paper, the existence and properties of a rho-function for the triple $(K, G, H)$ and an $N$-strongly quasi-invariant measure of double coset space $K \backslash G /H$ is investigated. In particular, it is shown that any such measure arises from a rho-function. Furthermore, the conditions under which an $N$-strongly quasi-invariant measure arises from a rho-function are studied.
On the frames by multiplication and irregular frames of translates on LCA groups
Volume 8, Issue 1, 2021, Pages 7-16
https://doi.org/10.22072/wala.2021.130732.1295
N.S. Seyedi, M. Mortazavizadeh, R. A. Kamyabi Gol
Abstract Let $X$ be a measure space and let $E$ be a measurable subset of $X$ with finite positive measure. In this paper, we investigate frame and Riesz basis properties of a family of functions multiplied by another measurable function in $L^2(E)$. Also, we study the equivalent conditions for a system of translates to be a Bessel family in $L^2(G)$ and to be a frame for $P_E$ (the space of the band limited functions). Finally, we study the properties of frames of translates that preserved by convolution.
مسأله گسترش و خواص جدیدی از $K$-قاب ها
Volume 7, 3 (Persian issue), 2021, Pages 1-17
https://doi.org/10.22072/wala.2019.108035.1224
وحیدرضا مرشدی, محمد جانفدا, رجبعلی کامیابی گل
Abstract
در این مقاله قصد داریم مفهوم گسترش هر دنباله بسل دلخواه در فضای هیلبرت تفکیکپذیر
$ \mathcal{H} $
را به یک
$K$-قاب چسبان برای
$ \mathcal{H} $
بیان و بررسی کنیم. همچنین گسترش دنباله های بسل به قابهای
$ K $
- دوگان را مورد مطالعه قرار میدهیم. به خصوص، مشخصهای را بیان میکنیم که بتوان با افزودن خانواده متناهی از بردارها به دنبالههای بسل آنها را به قابهای
$ K $
-دوگان تبدیل نمود.
Multiplication on double coset space $L^1(K\setminus G/H)$
Volume 7, Issue 1, 2020, Pages 37-46
https://doi.org/10.22072/wala.2020.119154.1262
F. Fahimian, R. A. Kamyabi-Gol, F. Esmaeelzadeh
Abstract
Consider a locally compact group $G$ with two compact subgroups $H$ and $K$. Equip the double coset space $K\setminus G/H$ with the quotient topology. Suppose that $\mu$ is an $N$-relatively invariant measure, on $K\setminus G/H$.
We define a multiplication on $L^1(K\setminus G/H,\mu)$ such that this space becomes a Banach algebra that possesses a left (right) approximate identity.
On a New G-Frame and Duality
Volume 5, Issue 1, 2018, Pages 1-9
https://doi.org/10.22072/wala.2017.51870.1089
Reihaneh Raisi Tousi, Rajab Ali Kamyabi Gol, Hosein Avazzadeh
Abstract We introduce a new g-frame (singleton g-frame), g-orthonormal basis and g-Riesz basis and study corresponding notions in some other generalizations of frames.
Also, we investigate duality for some kinds of g-frames. Finally, we illustrate an example which provides a suitable translation from discrete frames to Sun's g-frames.
Determination of subrepresentations of the standard higher dimensional shearlet group
Volume 4, Issue 1, 2017, Pages 11-21
https://doi.org/10.22072/wala.2017.23366
Masoumeh zare, Rajab ali Kamyabi-Gol, Zahra amiri
Abstract This paper is devoted to definition standard higher dimension shearlet group $ \mathbb{S} = \mathbb{R}^{+} \times \mathbb {R}^{n-1} \times \mathbb {R}^{n} $ and determination of square integrable subrepresentations of this group. Also we give a characterisation of admissible vectors associated to the Hilbert spaces corresponding to each su brepresentations.
Pseudoframe multiresolution structure on abelian locally compact groups
Volume 3, Issue 2, 2016, 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.