Volume 4 (2022)
Volume 3 (2021)
Volume 2 (2020)
Volume 1 (2019)
Number of Articles: 51
1. Non-stabilities of mixed type Euler-Lagrange k-cubic-quartic functional equation in various normed spaces
Volume 1, Issue 1 , February 2019, , Pages 1-43
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) = k2[2f(x+y) + f(x-y) + f(y-x)] + 2(k4-1) [f(x) + f(y)] +k2/4(k2-1) [f(2x) + f(2y)]where k is a real number ... Read More2. Toeplitzness of weighted composition operators
Volume 2, Issue 1 , April 2020, , Pages 1-8
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 defined by Cψ,φf= ψ·f°φ. In this paper, we study the asymptotically Toeplitzness ... Read More3. Analytic differenceability of functions
Volume 3, Issue 1 , February 2021, , Pages 1-12
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. Since the Bernoulli and Euler polynomials have many similarities, so it motivated us to define differenceability ... Read More4. Intuitionistic fuzzy stability of the heptic functional equation
Volume 3, Issue 2 , June 2021, , Pages 1-14
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 Rassias. This way shows that the concept of stability is related to some fixed point of a suitable operator. Read More5. On various types of compatible Jungck--Rhoades pairs of mappings in C*-algebra valued metric spaces
Volume 3, Issue 3 , September 2021, , Pages 1-25
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 types of mappings generalize from previously known ones within ordinary metric spaces. We have shown by examples ... Read More6. An existence result for a class of (p(x),q(x))-Laplacian system via sub-supersolution method
Volume 3, Issue 4 , December 2021, , Pages 1-8
Abstract
This study concerns the existence of positive solution for the following nonlinear boundary value problem\begin{gather*}-\Delta_{p(x)} u= a(x)h(u) + f(v) \quad\text{in }\Omega\\-\Delta_{q(x)} v=b(x)k(v) + g(u) \quad\text{in }\Omega\\u=v= 0 \quad\text{on } \partial \Omega\end{gather*}where $p(x),q(x) ... Read More7. Best simultaneous approximation in $L^{p}(S,X)$
Volume 4, Issue 1 , January 2022, , Pages 1-7
Abstract
As a counterpart to the best approximation in normed linear spaces, the best simultaneous approximation was introduced. In this paper, we shall consider relation between simultaneous proximinality $W$ in $X$ and $L^p(S,W)$ in $L^p(S,X)$ for $1\leq p\leq\infty$. Also, we consider the relation between ... Read More8. Some critical remarks of recent results on F-contractions in b-metric spaces
Volume 4, Issue 2 , April 2022, , Pages 1-10
Abstract
In this paper, we analyze, generalize and correct some recent results on F-contractions within b-metric spaces. In all results, our only assumption is the strict growth of the function F: $\left( 0,+\infty \right) \rightarrow \left( -\infty ,+\infty \right) .$ Read More9. A simple method to solve nonlinear Volterra-Fredholm integro-differential equations
Volume 2, Issue 1 , April 2020, , Pages 9-16
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 expansion a nonlinear Fredholm-Volterra integral equation converts to a nonlinear system. Some numerical examples ... Read More10. On closedness of convolution of two sets
Volume 3, Issue 4 , December 2021, , Pages 9-12
Abstract
In this note, we give an abstract version of the fact that convolution of two closed and compact subsets of a hypergroup is a closed set. Read More11. Perturbed second-order state-dependent Moreau's sweeping process
Volume 4, Issue 1 , January 2022, , Pages 9-23
Abstract
In this paper, using a discretization approach, the existence of solutions for a class of second-order differential inclusions is stated in finite dimensional setting. The right hand side of the problem is governed by the so-called nonconvex state-dependent sweeping process and contains a general perturbation ... Read More12. Automatic continuity of almost Jordan derivations on special Jordan Banach algebras
Volume 4, Issue 2 , April 2022, , Pages 11-16
Abstract
The following is the question form of Kaplansky conjecture of 1958. Is every derivation on semisimple Banach algebra continuous? Kaplansky conjecture was proved by Johnson and Sinclair in 1968. The concept of almost Jordan derivations on Jordan Banach algebras is introduced in this article. Also, Kaplansky ... Read More13. Generalized Ulam-Hyers stability of an alternate additive-quadratic-quartic functional equation in fuzzy Banach spaces
Volume 3, Issue 1 , February 2021, , Pages 13-31
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 More14. On a nonlinear abstract second-order integrodifferential equation part I
Volume 3, Issue 4 , December 2021, , Pages 13-24
Abstract
The object of this paper is to study the existence, uniqueness and continuation of the solutions of nonlinear second-order integrodifferential equations. In the theory of infinitesimal generator of $C_0$- semigroup in a Banach space, the fixed point theorems of Schauder and Banach are used to establish ... Read More15. On character amenability of weighted convolution algebras on certain semigroups
Volume 3, Issue 2 , June 2021, , Pages 15-26
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 locally finite idempotent set, inverse semigroups with a finite number of idempotents, Clifford semigroups and Rees matrix ... Read More16. The generalized Hyers–Ulam stability of derivations in non-Archimedean Banach algebras
Volume 2, Issue 1 , April 2020, , Pages 17-22
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 Banach algebras is established. Read More17. t-norms over fuzzy ideals (implicative, positive implicative) of BCK-algebras
Volume 4, Issue 2 , April 2022, , Pages 17-34
Abstract
In this paper, we use the notion of t-norms to introduce fuzzy subalgebras, fuzzy ideals, fuzzy implicative ideals, fuzzy positive implicative ideals in BCK-algebras. Next, we clarify the links between them and investigate their properties. Finally, we consider them under intersection, cartesian product ... Read More18. Locally finite inverse semigroups
Volume 2, Issue 1 , April 2020, , Pages 23-27
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 disjoint well-ordered countable chains. We also prove that whenS is a locally finite Clifford semigroup, S is ... Read More19. Numerical solution of a coupled system of fractional order integro differential equations by an efficient numerical method based on the second kind Chebyshev polynomials
Volume 3, Issue 4 , December 2021, , Pages 25-40
Abstract
In this paper, an efficient numerical method based on operational matrices of the second kind Chebyshev polynomials is used for the solution of a coupled system of fractional-order integrodifferential equations that the fractional derivative is given in Caputo's sense. The operational matrices of the ... Read More20. On the zeros and critical points of a polynomial
Volume 4, Issue 1 , January 2022, , Pages 25-28
Abstract
Let $P(z)=a_0 + a_1z + \dots + a_{n-1}z^{n-1}+z^n$ be a polynomial of degree $n.$ The Gauss-Lucas Theorem asserts that the zeros of the derivative $P^\prime (z)= a_1 + \dots +(n-1) a_{n-1}z^{n-2}+nz^{n-1},$ lie in the convex hull of the zeros of $P(z).$ Given a zero of ... Read More21. Fixed point results for generalized contractions in S-metric spaces
Volume 3, Issue 2 , June 2021, , Pages 27-39
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 and improve many well-known results in the existing literature. Read More22. A new version of the Hahn Banach theorem in b-Banach spaces
Volume 3, Issue 3 , September 2021, , Pages 27-32
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 application. Read More23. Certain dense subalgebras of continuous vector-valued operator algebras
Volume 2, Issue 1 , April 2020, , Pages 28-34
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 that C(X,B) be the continuous, A(X,B) be the analytic, and Lipα(X,B) be the α-Lipschitz B-valued ... Read More24. Bicomplex valued bipolar metric spaces and fixed point theorems
Volume 4, Issue 1 , January 2022, , Pages 29-43
Abstract
The concept of bicomplex valued bipolar metric space is introduced in this article, and some properties are derived. Also, some fixed point results of contravariant maps satisfying rational inequalities are proved for bicomplex valued bipolar metric spaces. Read More25. Some results on disjointness preserving Fredholm operators between certain Banach function algebras
Volume 3, Issue 1 , February 2021, , Pages 32-39