Functional analysis
1. A new implicit iteration process for approximating common fixed points of $\alpha$-demicontraction semigroup

A. E. Ofem; D. I. Igbokwe

Volume 10, Issue 01 , Winter 2021, , Pages 19-34

Abstract
  It is our purpose in this paper to introduce the concept of $\alpha$-demicontractive semigroup. Also, we construct a new implicit iterative scheme for approximating the common fixed points of $\alpha$-demicontractive semigroup. We prove strong convergence of our new iterative scheme to the common fixed ...  Read More

Functional analysis
2. On new types of contraction mappings in bipolar metric spaces and applications

G. N. V. Kishore; H. Işık; H. Aydi; B. S. Rao; D. R. Prasad

Volume 09, Issue 04 , Autumn 2020, , Pages 253-266

Abstract
  Our aim is to present some common fixed point theorems in bipolar metric spaces via certain contractive conditions. Some  examples have been provided to illustrate the effectiveness of new results. At the end, we give two applications dealing with homotopy theory and integral equations.  Read More

Functional analysis
3. Some improvements of numerical radius inequalities via Specht’s ratio

Y. Khatib; M. Hassani

Volume 09, Issue 03 , Summer 2020, , Pages 221-230

Abstract
  We obtain some inequalities related to the powers of numerical radius inequalities of Hilbert space operators. Some results that employ the Hermite-Hadamard inequality for vectors in normed linear spaces are also obtained. We improve and generalize some inequalities with respect to ...  Read More

Functional analysis
4. Approximation of endpoints for multi-valued mappings in metric spaces

K. Ullah; J. Ahmad; N. Muhammad

Volume 09, Issue 02 , Spring 2020, , Pages 129-137

Abstract
  In this paper, under some appropriate conditions, we prove some $\Delta$ and strong convergence theorems of endpoints for multi-valued nonexpansive mappings using modified Agarwal-O'Regan-Sahu iterative process in the general setting of 2-uniformly convex hyperbolic spaces. Our results extend and unify ...  Read More

Functional analysis
5. Fixed points of generalized $\alpha$-Meir-Keeler type contractions and Meir-Keeler contractions through rational expression in $b$-metric-like spaces

N. Gholamian

Volume 09, Issue 01 , Winter 2020, , Pages 17-34

Abstract
  In this paper, we first introduce some types of generalized $\alpha$-Meir-Keeler contractions in $b$-metric-like spaces and then we establish some fixed point results for these types of contractions. Also, we present a new fixed point theorem for a Meir-Keeler contraction through rational expression. ...  Read More

Integral equations
6. Hyers–Ulam–Rassias stability of impulsive Volterra integral equation via a fixed point approach

R. Shah; A. Zada

Volume 08, Issue 04 , Autumn 2019, , Pages 219-227

Abstract
  ‎In this paper‎, ‎we establish the Hyers--Ulam--Rassias stability and the Hyers--Ulam stability of impulsive Volterra integral equation by using a fixed point method‎.  Read More

Integral equations
7. New iteration process for approximating fixed points in Banach spaces

J. D. Bhutia; K. Tiwary

Volume 08, Issue 04 , Autumn 2019, , Pages 237-250

Abstract
  ‎The object of this paper is to present a new iteration process‎. ‎We will show that our process is faster than the known recent iterative schemes‎. ‎We discuss stability results of our iteration and prove some results in the context of uniformly convex Banach space for Suzuki generalized ...  Read More

Functional analysis
8. 2n-Weak module amenability of semigroup algebras

K. Fallahi; H. Ghahramani

Volume 08, Issue 03 , Summer 2019, , Pages 203-209

Abstract
  ‎Let $S$ be an inverse semigroup with the set of idempotents $E$‎. We prove that the semigroup algebra $\ell^{1}(S)$ is always‎ ‎$2n$-weakly module amenable as an $\ell^{1}(E)$-module‎, ‎for any‎ ‎$n\in \mathbb{N}$‎, ‎where $E$ acts on $S$ trivially ...  Read More

Functional analysis
9. Operator frame for $End_{\mathcal{A}}^{\ast}(\mathcal{H})$

M. Rossafi; S. Kabbaj

Volume 08, Issue 02 , Spring 2019, , Pages 85-95

Abstract
  ‎Frames generalize orthonormal bases and allow representation of all the elements of the space‎. ‎Frames play significant role in signal and image processing‎, ‎which leads to many applications in informatics‎, ‎engineering‎, ‎medicine‎, ‎and probability‎. ...  Read More

Functional analysis
10. Best proximity point theorems in 1/2−modular metric spaces

H. Hosseini; M. Eshaghi Gordji

Volume 08, Issue 02 , Spring 2019, , Pages 145-158

Abstract
  ‎In this paper‎, ‎first we introduce the notion of $\frac{1}{2}$-modular metric spaces and weak $(\alpha,\Theta)$-$\omega$-contractions in this spaces and we establish some results of best proximity points‎. ‎Finally‎, ‎as consequences of these theorems‎, ‎we derive ...  Read More

Linear and multilinear algebra; matrix theory
11. *-frames in Hilbert modules over pro-C*-algebras

M. Naroei Irani; A. Nazari

Volume 08, Issue 01 , Winter 2019, , Pages 1-10

Abstract
  ‎In this paper‎, ‎by using the sequence of multipliers‎, ‎we introduce frames with algebraic bounds in Hilbert pro-$ C^* $-modules‎. ‎We investigate the relations between frames and $ \ast $-frames‎. ‎Some properties of $ \ast $-frames in Hilbert pro-$ C^* $-modules ...  Read More

Functional analysis
12. System of AQC functional equations in non-Archimedean normed spaces

H. Majani

Volume 08, Issue 01 , Winter 2019, , Pages 41-52

Abstract
  ‎In 1897‎, ‎Hensel introduced a normed space which does‎ ‎not have the Archimedean property‎. ‎During the last three decades‎ ‎theory of non--Archimedean spaces has gained the interest of‎ ‎physicists for their research in particular in problems ...  Read More

Functional analysis
13. A new type of Hyers-Ulam-Rassias stability for Drygas functional equation

M. Sirouni; M. ‎Almahalebi; S. ‎Kabbaj

Volume 07, Issue 04 , Autumn 2018, , Pages 251-260

Abstract
  In this paper, we prove the generalized Hyers-Ulam-Rassias stability for the Drygas functional equation$$f(x+y)+f(x-y)=2f(x)+f(y)+f(-y)$$ in Banach spaces by using the Brz\c{d}ek's fixed point theorem. Moreover, we give a general result on the hyperstability of this equation. Our results are improvements ...  Read More

Functional analysis
14. A note on spectral mapping theorem

Z. Heydarbeygi; B. Moosavi; M. Shah Hosseini

Volume 07, Issue 04 , Autumn 2018, , Pages 269-272

Abstract
  This paper aims to present the well-known spectral mapping theorem for multi-variable functions.  Read More

Functional analysis
15. On a new type of stability of a radical cubic functional equation related to Jensen mapping

S. A. A. AL-Ali; Y. Elkettani

Volume 07, Issue 04 , Autumn 2018, , Pages 281-292

Abstract
  ‎The aim of this paper is to introduce and solve the‎ radical cubic functional equation‎ ‎$‎‎f\left(\sqrt[3]{x^{3}+y^{3}}\right)+f\left(\sqrt[3]{x^{3}-y^{3}}\right)=2f(x)‎$.‎ ‎We also investigate some stability and hyperstability results for‎ ‎the ...  Read More

Functional analysis
16. $\ast$-K-g-Frames in Hilbert $\mathcal{A}$-modules

M. Rossafi; S. Kabbaj

Volume 07, Issue 01 , Winter 2018, , Pages 63-71

Abstract
  In this paper, we introduce the concepts of $\ast$-K-g-Frames in Hilbert $\mathcal{A}$-modules and we establish some results.  Read More

Abstract harmonic analysis
18. Classical Wavelet Transforms over Finite Fields

A. Ghaani Farashahi

Volume 04, Issue 04 , Autumn 2015, , Pages 241-257

Abstract
  This article introduces a systematic study for computational aspects of classical wavelet transforms over finite fields using tools from computational harmonic analysis and also theoretical linear algebra. We present a concrete formulation for the Frobenius norm of the classical wavelet transforms over ...  Read More

Functional analysis
19. Duals and approximate duals of g-frames in Hilbert spaces

M. Mirzaee Azandaryani; A. Khosravi

Volume 04, Issue 04 , Autumn 2015, , Pages 259-265

Abstract
  In this paper we get some results and applications for duals and approximate duals of g-frames in Hilbert spaces. In particular, we consider the stability of duals and approximate duals under bounded operators and we study duals and approximate duals of g-frames in the direct sum of Hilbert spaces. We ...  Read More

Functional analysis
20. New characterizations of fusion bases and Riesz fusion bases in Hilbert spaces

F. Aboutorabi Goudarzi; M. S. Asgari

Volume 04, Issue 02 , Spring 2015, , Pages 131-142

Abstract
  In this paper we investigate a new notion of bases in Hilbert spaces and similar to fusion frame theory we introduce fusion bases theory in Hilbert spaces. We also introduce a new de nition of fusion dual sequence associated with a fusion basis and show that the operators of a fusion dual ...  Read More

Functional analysis
21. Upper and lower $\alpha(\mu_{X},\mu_{Y})$-continuous multifunctions

M. Akdag; F. Erol

Volume 04, Issue 01 , Winter 2015, , Pages 1-9

Abstract
  In this paper, a new class of multifunctions, called generalized $\alpha(\mu_{X},\mu_{Y})$-continuous multifunctions, has been de ned and studied. Some characterizations and several properties concerning generalized $\alpha(\mu_{X},\mu_{Y})$-continuous multifunctions are obtained. The relationships ...  Read More

Functional analysis
22. Frames for compressed sensing using coherence

L. Gavruta; G. Zamani Eskandani; P. Gavruta

Volume 04, Issue 01 , Winter 2015, , Pages 25-34

Abstract
  We give some new results on sparse signal recovery in the presence of noise, for weighted spaces. Traditionally, were used dictionaries that have the norm equal to 1, but, for random dictionaries this condition is rarely satis ed. Moreover, we give better estimations then the ones given ...  Read More

Functional analysis
23. The solutions to some operator equations in Hilbert $C^*$-module

M. Mohammadzadeh Karizaki; M. Hassani

Volume 04, Issue 01 , Winter 2015, , Pages 35-42

Abstract
  In this paper, we state some results on product of operators with closed ranges and we solve the operator equation $TXS^*-SX^*T^*= A$ in the general setting of the adjointable operators between Hilbert $C^*$-modules, when $TS = 1$. Furthermore, by using some block operator matrix techniques, ...  Read More

Integral equations
24. Numerical solution of Fredholm integral-differential equations on unbounded domain

M. Matinfar; A. Riahifar

Volume 04, Issue 01 , Winter 2015, , Pages 43-52

Abstract
  In this study, a new and efficient approach is presented for numerical solution of Fredholm integro-differential equations (FIDEs) of the second kind on unbounded domain with degenerate kernel based on operational matrices with respect to generalized Laguerre polynomials(GLPs). Properties ...  Read More

Functional analysis
25. On duality of modular G-Riesz bases and G-Riesz bases in Hilbert C*-modules

M. Rashidi-Kouchi

Volume 04, Issue 01 , Winter 2015, , Pages 53-63

Abstract
  In this paper, we investigate duality of modular g-Riesz bases and g-Riesz bases in Hilbert C*-modules. First we give some characterization of g-Riesz bases in Hilbert C*-modules, by using properties of operator theory. Next, we characterize the duals of a given g-Riesz basis in Hilbert C*-module. ...  Read More