Research Paper Functional analysis
1. 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

Research Paper Algebraic topology
2. Linear \v{C}ech closure spaces

T. M. Chacko; D. Susha

Volume 07, Issue 04 , Autumn 2018, Pages 261-268

Abstract
  In this paper, we introduce the concept of linear \v{C}ech closure spaces and establish the properties of open sets in linear \v{C}ech closure spaces (L\v{C}CS). Here, we observe that the concept of linearity is preserved by semi-open sets, g-semi open sets, $\gamma$-open sets, sgc-dense sets and compact ...  Read More

Research Paper Functional analysis
3. 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

Research Paper Operator theory
4. Algebraic distance in algebraic cone metric spaces and its properties

K. Fallahi; G. Soleimani Rad

Volume 07, Issue 04 , Autumn 2018, Pages 273-280

Abstract
  In this paper, we prove some properties of algebraic cone metric spaces and introduce the notion of algebraic distance in an algebraic cone metric space. As an application, we obtain some famous fixed point results in the framework of this algebraic distance.  Read More

Research Paper Functional analysis
5. 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

Research Paper Algebraic topology
6. Digital cohomology groups of certain minimal surfaces

I. Karaca; O. Ege

Volume 07, Issue 04 , Autumn 2018, Pages 293-305

Abstract
  In this study, we compute simplicial cohomology groups with different coefficients of a connected sum of certain minimal simple surfaces by using the universal coefficient theorem for cohomology groups. The method used in this paper is a different way to compute digital cohomology groups ...  Read More

Research Paper Linear and multilinear algebra; matrix theory
7. On the solving matrix equations by using the spectral representation

A. M. Nazari; S. Mollaghasemi; F. Bahmani

Volume 07, Issue 04 , Autumn 2018, Pages 307-316

Abstract
  ‎The purpose of this paper is to solve two types of Lyapunov equations and quadratic matrix equations by using the spectral representation‎. ‎We focus on solving Lyapunov equations $AX+XA^*=C$ and $AX+XA^{T}=-bb^{T}$ for $A‎, ‎X \in \mathbb{C}^{n \times n}$ and $b \in \mathbb{C} ^{n ...  Read More