Non-stabilities of mixed type Euler-Lagrange k-cubic-quartic functional equation in various normed spaces
1. Non-stabilities of mixed type Euler-Lagrange k-cubic-quartic functional equation in various normed spaces

John Michael Rassias; Mohan Arunkumar; Elumalai Sathya

Volume 1, Issue 1 , Winter 2019, , Pages 1-43

http://dx.doi.org/10.30495/maca.2019.679849

Abstract
  In this paper, we introduce and examine the generalized Ulam-Hyers stability of fixed Euler-Lagrange  k-Cubic-Quartic functional Equationf(x+ky) + f(kx+y) + f(x-ky) + f(y-kx) = ...  Read More
Toeplitzness of weighted composition operators
2. Toeplitzness of weighted composition operators

Massoud Salehi Sarvestani

Volume 2, Issue 1 , Spring 2020, , Pages 1-8

http://dx.doi.org/10.30495/maca.2020.679850

Abstract
  For a bounded analytic map ψ on the unit disk D and analytic self-map  φ of D, a weighted composition operator Cψ,φ on the Hardy space H2=H2(D) is ...  Read More
Analytic differenceability of functions
3. Analytic differenceability of functions

Soodeh Mehboodi; Mohammad Hadi Hooshmand

Volume 3, Issue 1 , Winter 2021, , Pages 1-12

http://dx.doi.org/10.30495/maca.2021.680048

Abstract
  Analytic summability of functions was introduced by Hooshmand in 2016. He used Bernoulli numbers and polynomials Bn(z) to define analytic summability and related analytic summand functions. ...  Read More
Intuitionistic fuzzy stability of the heptic functional equation
4. Intuitionistic fuzzy stability of the heptic functional equation

Mohammad Shafii Mousavi

Volume 3, Issue 2 , Spring 2021, , Pages 1-14

http://dx.doi.org/10.30495/maca.2021.1926769.1006

Abstract
  In this article, by using a fixed point method, we establish the intuitionistic fuzzy version of Hyers-Ulam stability for a heptic functional equation that was introduced by Xu and ...  Read More
On various types of compatible Jungck--Rhoades pairs of mappings in C*-algebra valued metric spaces
5. On various types of compatible Jungck--Rhoades pairs of mappings in C*-algebra valued metric spaces

Parveen Kumar; Nicola Fabiano; Ljiljana Paunovic

Volume 3, Issue 3 , Summer 2021, , Pages 1-25

http://dx.doi.org/10.30495/maca.2021.1932335.1014

Abstract
  In this paper, among other things, we have established four different types of compatible mappings that work in the context of C*-algebra valued metric spaces. The obtained ...  Read More
A simple method to solve nonlinear Volterra-Fredholm integro-differential equations
6. A simple method to solve nonlinear Volterra-Fredholm integro-differential equations

Mohsen Mohamadi; Amir Shahmari

Volume 2, Issue 1 , Spring 2020, , Pages 9-16

http://dx.doi.org/10.30495/maca.2020.679851

Abstract
  In this paper, a new simple direct method to solve nonlinear Fredholm-Volterra integral equations is presented. By using Block-pulse (BP) functions, their operational matrices and Taylor ...  Read More
Generalized Ulam-Hyers stability of an alternate additive-quadratic-quartic functional equation in fuzzy Banach spaces
7. Generalized Ulam-Hyers stability of an alternate additive-quadratic-quartic functional equation in fuzzy Banach spaces

John Michael Rassias; Elumalai Sathya; Mohan Arunkumar

Volume 3, Issue 1 , Winter 2021, , Pages 13-31

http://dx.doi.org/10.30495/maca.2021.680135

Abstract
  In this paper, we obtain and establish the generalized Ulam-Hyers stability of an additive-quadratic-quartic functional equation in fuzzy Banach spaces.  Read More
On character amenability of weighted convolution algebras on certain semigroups
8. On character amenability of weighted convolution algebras on certain semigroups

Kobra Oustad

Volume 3, Issue 2 , Spring 2021, , Pages 15-26

http://dx.doi.org/10.30495/maca.2021.1928647.1007

Abstract
  In this work, we study the character amenability of weighted convolution algebras $\ell^{1} (S,\omega)$, where $ S $ is a semigroup of classes of inverse semigroups with a uniformly ...  Read More
The generalized Hyers–Ulam stability of derivations in non-Archimedean Banach algebras
9. The generalized Hyers–Ulam stability of derivations in non-Archimedean Banach algebras

Abolfazl Niazi Motlagh

Volume 2, Issue 1 , Spring 2020, , Pages 17-22

http://dx.doi.org/10.30495/maca.2020.679852

Abstract
  In this paper, the generalized Hyers-Ulam stability of the functional inequality||f(a)+f(b)+cf(d)+f(c)d||≤||kf((a+b+cd)/k)||,      |k|<|2|,in non-Archimedean ...  Read More
Locally finite inverse semigroups
10. Locally finite inverse semigroups

Somaye Grailoo Tanha

Volume 2, Issue 1 , Spring 2020, , Pages 23-27

http://dx.doi.org/10.30495/maca.2020.679854

Abstract
  In this article, we study locally finite inverse semigroup S and characterize the structure of idempotents of S which are either a well-ordered countable chain or union of ...  Read More
Fixed point results for generalized contractions in S-metric spaces
11. Fixed point results for generalized contractions in S-metric spaces

Khalil Javed; Fahim Uddin; Faizan Adeel; Muhammad Arshad; Hossein Alaeidizaji; Vahid Parvaneh

Volume 3, Issue 2 , Spring 2021, , Pages 27-39

http://dx.doi.org/10.30495/maca.2021.1929557.1009

Abstract
  In this paper, we discuss the existence of a fixed point for a generalized contraction in S-metric spaces. We furnish some examples in support of our main results. Our results generalize ...  Read More
A new version of the Hahn Banach theorem in b-Banach spaces
12. A new version of the Hahn Banach theorem in b-Banach spaces

Mohammad Reza Haddadi; Hossein Alaeidizaji; Vahid Parvaneh

Volume 3, Issue 3 , Summer 2021, , Pages 27-32

http://dx.doi.org/10.30495/maca.2021.1929965.1011

Abstract
  In this paper, we introduce the notion of b-Banach spaces and we present some examples. Also, we give an important extension of the Hahn-Banach theorem in a $b$-Banach space with an ...  Read More
Certain dense subalgebras of continuous vector-valued operator algebras
13. Certain dense subalgebras of continuous vector-valued operator algebras

Abbasali Shokri

Volume 2, Issue 1 , Spring 2020, , Pages 28-34

http://dx.doi.org/10.30495/maca.2020.679855

Abstract
  Let X be a compact metric space with at least two elements, B be a unital commutative Banach algebra over the scalar field F=R or C, and α in R with 0<α≤1. Suppose ...  Read More
Some results on disjointness preserving Fredholm operators between certain Banach function algebras
14. Some results on disjointness preserving Fredholm operators between certain Banach function algebras

Lida Mousavi; Sedigheh Hosseini

Volume 3, Issue 1 , Winter 2021, , Pages 32-39

http://dx.doi.org/10.30495/maca.2021.1924698.1002

Abstract
  For two algebras $\A$ and $\B$, a linear map $T : \A \lo \B$ is disjointness preserving if $x \cdot y = 0$ implies $Tx \cdot Ty = 0$ for all $x, y \in \A$ and is said ...  Read More
On Palais method in b-metric like spaces
15. On Palais method in b-metric like spaces

Nikola Mirkov; Zoran D. Mitrovic; Mudasir Younis; Stjan Radenovic

Volume 3, Issue 3 , Summer 2021, , Pages 33-38

http://dx.doi.org/10.30495/maca.2021.1932449.1015

Abstract
  This paper aims to prove that the Lipschitz constant in the Banach contraction principle belongs to the whole interval [0, 1) for all the six classes of spaces viz. metric spaces, b-metric ...  Read More
A new notion of affine sets
16. A new notion of affine sets

Paulraj Gnanachandra; Mohan Arunkumar

Volume 2, Issue 1 , Spring 2020, , Pages 35-42

http://dx.doi.org/10.30495/maca.2020.679857

Abstract
  In this paper, we investigate the behaviour of e-convex sets and e-affine sets. Moreover, some notions like S(e,a,ρ,α) and e-affine cones are introduced and discussed. We ...  Read More
Weakly principally quasi-Baer rings and generalized triangular matrix rings
17. Weakly principally quasi-Baer rings and generalized triangular matrix rings

Kamal Paykan

Volume 3, Issue 1 , Winter 2021, , Pages 39-45

http://dx.doi.org/10.30495/maca.2021.1925653.1004

Abstract
  A ring $R$ is called weakly principally quasi-Baer or simply (weakly p.q.-Baer) if the right annihilator of a principal right ideal is right $s$-unital by right semicentral ...  Read More
On quasi hemi-slant submanifolds of LP-cosymplectic manifolds
18. On quasi hemi-slant submanifolds of LP-cosymplectic manifolds

Siddesha M S; Praveena M M; Bagewadi C S

Volume 3, Issue 3 , Summer 2021, , Pages 39-49

http://dx.doi.org/10.30495/maca.2021.1934998.1016

Abstract
  In this paper, we define and study quasi Hemi-slant submanifolds of Lorentzian almost contact metric manifolds. We mainly concern with quasi Hemi-slant submanifolds of LP-cosymplectic ...  Read More
Some coupled coincidence point results in partially ordered metric spaces
19. Some coupled coincidence point results in partially ordered metric spaces

Laya Fadakar; Huseyin Işık; Shirin Tavakoli; Arezo Mardzad

Volume 3, Issue 2 , Spring 2021, , Pages 40-54

http://dx.doi.org/10.30495/maca.2021.1929674.1010

Abstract
  In this paper, we introduce the notion of partial-compatibility of mappings in an ordered partial metric space and use this notion to establish coupled coincidence point theorems for ...  Read More
Stability of cosine type functional equations onmodule extension Banach algebras
20. Stability of cosine type functional equations onmodule extension Banach algebras

Abbas Zivari-Kazempour

Volume 1, Issue 1 , Winter 2019, , Pages 44-49

http://dx.doi.org/10.30495/maca.2021.679842

Abstract
  Let A be a Banach algebra and X be a Banach A-bimodule. In this paper we investigate the stability of the cosine type functional equation φ(ab,a·y+x·b)=φ(ab,x·b-a·y)=2φ(a,x)φ(b,y),on ...  Read More
A proof of the Cauchy--Schwarz inequality from the change of reference frame
21. A proof of the Cauchy--Schwarz inequality from the change of reference frame

Nicola Fabiano

Volume 3, Issue 1 , Winter 2021, , Pages 46-47

http://dx.doi.org/10.30495/maca.2021.1927475.1005

Abstract
  Inspired by [1] a proof of the Cauchy--Schwarz inequality is given by considering the transformation between two different inertial reference frames.  Read More
Stability of quartic functional equation in paranormed spaces
22. Stability of quartic functional equation in paranormed spaces

Karthikeyan Subramani; Choonkil Park; John Michael Rassias

Volume 3, Issue 1 , Winter 2021, , Pages 48-58

http://dx.doi.org/10.30495/maca.2021.1924046.1001

Abstract
  In this paper, we prove the Ulam-Hyers stability of the following quartic functional equation in paranormed spaces using both direct and fixed point methods.  Read More
Partially ordered cone metric spaces and coupled fixed point theorems via $\alpha$-series
23. Partially ordered cone metric spaces and coupled fixed point theorems via $\alpha$-series

Samira Hadi Bonab; Rasoul Abazari; Ali Bagheri Vakilabad

Volume 1, Issue 1 , Winter 2019, , Pages 50-61

http://dx.doi.org/10.30495/maca.2019.679847

Abstract
  This research tends to focus on proving the results of coupled fixed point in partially ordered cone metric spaces by imposing some condition on a self-mapping and a sequence of mappings ...  Read More
Some approximations for an equation in modular spaces
24. Some approximations for an equation in modular spaces

Mehdi Salehi Barough

Volume 3, Issue 3 , Summer 2021, , Pages 51-64

http://dx.doi.org/10.30495/maca.2021.1935651.1018

Abstract
  In this paper, we introduce and obtain the general solution of a new mixed type quadratic-cubic functional equation. We investigate the stability of such functional equations in the ...  Read More
The coincidence point results and rational contractions in E(s)-distance spaces
25. The coincidence point results and rational contractions in E(s)-distance spaces

Maliha Rashid; Rabia Bibi; Reny George; Zoran D. Mitrovic

Volume 3, Issue 2 , Spring 2021, , Pages 55-67

http://dx.doi.org/10.30495/maca.2021.1931683.1012

Abstract
  The purpose of this article is to clarify the concept of semi-interior points of positive cones by presenting some results and examples in this context.  Moreover, the new concept ...  Read More