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Keywords = q-symmetric differential operator

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20 pages, 1668 KB  
Article
Geometric Properties and Applications in System Modeling for a Generalized q-Symmetric Operator
by Abdelrahman M. Yehia, Atef F. Hashem, A. S. Al-Moisheer, Mohamed A. Sohaly, Samar M. Madian and Mohammed M. Tharwat
Symmetry 2025, 17(10), 1593; https://doi.org/10.3390/sym17101593 - 24 Sep 2025
Viewed by 240
Abstract
This paper introduces a novel generalized q-symmetric differential operator for studying a certain subclass of univalent functions with negative coefficients. We establish several significant theoretical results for this class, including sharp coefficient bounds and characterization theorems based on the generalized Hadamard product. [...] Read more.
This paper introduces a novel generalized q-symmetric differential operator for studying a certain subclass of univalent functions with negative coefficients. We establish several significant theoretical results for this class, including sharp coefficient bounds and characterization theorems based on the generalized Hadamard product. Two significant applications demonstrate the theoretical framework’s practical utility. First, in the context of geometric modeling, we demonstrate how the function class and operator can be utilized to create and control complex, non-overlapping transformations. Second, in digital signal processing, we show that these functions serve as stable digital filter prototypes and that our operator is an effective tool for fine-tuning the filter’s frequency response. These applications bridge the gap between abstract geometric function theory and practical system design by demonstrating the operator’s versatility as a tool for analysis and synthesis. Full article
(This article belongs to the Special Issue Symmetry in Complex Analysis Operators Theory)
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23 pages, 345 KB  
Article
On Certain Subclasses of Analytic Functions Associated with a Symmetric q-Differential Operator
by Vasile-Aurel Caus
Mathematics 2025, 13(17), 2860; https://doi.org/10.3390/math13172860 - 4 Sep 2025
Viewed by 574
Abstract
This paper explores a class of analytic functions defined in the open unit disk by means of a symmetric q-differential operator. In the first part, we derive sufficient conditions for functions to belong to a subclass associated with this operator, using inequalities [...] Read more.
This paper explores a class of analytic functions defined in the open unit disk by means of a symmetric q-differential operator. In the first part, we derive sufficient conditions for functions to belong to a subclass associated with this operator, using inequalities involving their coefficients. Additionally, we establish several inclusion relations between these subclasses, obtained by varying the defining parameters. In the second part, we focus on differential subordination and superordination for functions transformed by the operator. We provide sufficient conditions under which such functions are subordinate or superordinate to univalent functions, and we determine the best dominant and best subordinant in specific cases. These results are complemented by several corollaries that highlight particular instances of the main theorems. Furthermore, we present a sandwich-type result that brings together the subordination and superordination frameworks in a unified analytic statement. Full article
(This article belongs to the Special Issue Current Topics in Geometric Function Theory, 2nd Edition)
14 pages, 569 KB  
Article
A New Subclass of Bi-Univalent Functions Defined by Subordination to Laguerre Polynomials and the (p,q)-Derivative Operator
by Mohammad El-Ityan, Tariq Al-Hawary, Basem Aref Frasin and Ibtisam Aldawish
Symmetry 2025, 17(7), 982; https://doi.org/10.3390/sym17070982 - 21 Jun 2025
Cited by 4 | Viewed by 701
Abstract
In this work, we introduce a new subclass of bi-univalent functions using the (p,q)-derivative operator and the concept of subordination to generalized Laguerre polynomials Ltς(k), which satisfy the differential equation [...] Read more.
In this work, we introduce a new subclass of bi-univalent functions using the (p,q)-derivative operator and the concept of subordination to generalized Laguerre polynomials Ltς(k), which satisfy the differential equation ky+(1+ςk)y+ty=0, with 1+ς>0, kR, and t0. We focus on functions that blend the geometric features of starlike and convex mappings in a symmetric setting. The main goal is to estimate the initial coefficients of functions in this new class. Specifically, we obtain sharp upper bounds for |a2| and |a3| and for the Fekete–Szegö functional |a3ηa22| for some real number η. In the final section, we explore several special cases that arise from our general results. These results contribute to the ongoing development of bi-univalent function theory in the context of (p,q)-calculus. Full article
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19 pages, 1200 KB  
Article
A Subclass of Meromorphic Multivalent Functions Generated by a Symmetric q-Difference Operator
by Vasile-Aurel Caus
Mathematics 2025, 13(11), 1797; https://doi.org/10.3390/math13111797 - 28 May 2025
Cited by 1 | Viewed by 491
Abstract
This paper presents a novel symmetric q-analogue differential operator designed for meromorphic multivalent functions analytic in the punctured open unit disk. Employing this operator, a new family of meromorphic multivalent functions is proposed and examined in this work. A detailed investigation of [...] Read more.
This paper presents a novel symmetric q-analogue differential operator designed for meromorphic multivalent functions analytic in the punctured open unit disk. Employing this operator, a new family of meromorphic multivalent functions is proposed and examined in this work. A detailed investigation of this newly defined class of meromorphic multivalent functions is presented, highlighting key geometric characteristics, including sufficiency criteria, coefficient inequalities, distortion and growth behavior, as well as the radii of starlikeness and convexity. Full article
(This article belongs to the Section C4: Complex Analysis)
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20 pages, 300 KB  
Article
A Class of Symmetric Harmonic Functions Involving a Specific q-Difference Symmetric Operator
by Loriana Andrei and Vasile-Aurel Caus
Symmetry 2025, 17(5), 721; https://doi.org/10.3390/sym17050721 - 8 May 2025
Cited by 3 | Viewed by 506
Abstract
This paper introduces a new class of harmonic functions defined through a generalized symmetric q-differential that acts on both the analytic and co-analytic parts of the function. By combining concepts from symmetric q-calculus and geometric function theory, we develop a framework [...] Read more.
This paper introduces a new class of harmonic functions defined through a generalized symmetric q-differential that acts on both the analytic and co-analytic parts of the function. By combining concepts from symmetric q-calculus and geometric function theory, we develop a framework that extends several well-known operators as special cases. The main contributions of this study include new criteria for harmonic univalence, sharp coefficient bounds, distortion theorems, and covering results. Our operator offers increased flexibility in modeling symmetric structures, with potential applications in complex analysis, fractional calculus, and mathematical physics. To support these theoretical developments, we provide concrete examples and highlight potential directions for future research, including extensions to higher-dimensional settings. Full article
(This article belongs to the Special Issue Symmetry in Geometric Theory of Analytic Functions)
25 pages, 722 KB  
Article
Numerical Approximations and Fractional Calculus: Extending Boole’s Rule with Riemann–Liouville Fractional Integral Inequalities
by Abdul Mateen, Wali Haider, Asia Shehzadi, Hüseyin Budak and Bandar Bin-Mohsin
Fractal Fract. 2025, 9(1), 52; https://doi.org/10.3390/fractalfract9010052 - 18 Jan 2025
Viewed by 1514
Abstract
This paper develops integral inequalities for first-order differentiable convex functions within the framework of fractional calculus, extending Boole-type inequalities to this domain. An integral equality involving Riemann–Liouville fractional integrals is established, forming the foundation for deriving novel fractional Boole-type inequalities tailored to differentiable [...] Read more.
This paper develops integral inequalities for first-order differentiable convex functions within the framework of fractional calculus, extending Boole-type inequalities to this domain. An integral equality involving Riemann–Liouville fractional integrals is established, forming the foundation for deriving novel fractional Boole-type inequalities tailored to differentiable convex functions. The proposed framework encompasses a wide range of functional classes, including Lipschitzian functions, bounded functions, convex functions, and functions of bounded variation, thereby broadening the applicability of these inequalities to diverse mathematical settings. The research emphasizes the importance of the Riemann–Liouville fractional operator in solving problems related to non-integer-order differentiation, highlighting its pivotal role in enhancing classical inequalities. These newly established inequalities offer sharper error bounds for various numerical quadrature formulas in classical calculus, marking a significant advancement in computational mathematics. Numerical examples, computational analysis, applications to quadrature formulas and graphical illustrations substantiate the efficacy of the proposed inequalities in improving the accuracy of integral approximations, particularly within the context of fractional calculus. Future directions for this research include extending the framework to incorporate q-calculus, symmetrized q-calculus, alternative fractional operators, multiplicative calculus, and multidimensional spaces. These extensions would enable a comprehensive exploration of Boole’s formula and its associated error bounds, providing deeper insights into its performance across a broader range of mathematical and computational settings. Full article
(This article belongs to the Section General Mathematics, Analysis)
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20 pages, 304 KB  
Article
Derivation of Tensor Algebra as a Fundamental Operation—The Fermi Derivative in a General Metric Affine Space
by Michael Tsamparlis
Symmetry 2025, 17(1), 81; https://doi.org/10.3390/sym17010081 - 7 Jan 2025
Viewed by 1094
Abstract
The aim of this work is to demonstrate that all linear derivatives of the tensor algebra over a smooth manifold M can be viewed as specific cases of a broader concept—the operation of derivation. This approach reveals the universal role of differentiation, which [...] Read more.
The aim of this work is to demonstrate that all linear derivatives of the tensor algebra over a smooth manifold M can be viewed as specific cases of a broader concept—the operation of derivation. This approach reveals the universal role of differentiation, which simplifies and generalizes the study of tensor derivatives, making it a powerful tool in Differential Geometry and related fields. To perform this, the generic derivative is introduced, which is defined in terms of the quantities Qk(i)(X). Subsequently, the transformation law of these quantities is determined by the requirement that the generic derivative of a tensor is a tensor. The quantities Qk(i)(X) and their transformation law define a specific geometric object on M, and consequently, a geometric structure on M. Using the generic derivative, one defines the tensor fields of torsion and curvature and computes them for all linear derivatives in terms of the quantities Qk(i)(X). The general model is applied to the cases of Lie derivative, covariant derivative, and Fermi derivative. It is shown that the Lie derivative has non-zero torsion and zero curvature due to the Jacobi identity. For the covariant derivative, the standard results follow without any further calculations. Concerning the Fermi derivative, this is defined in a new way, i.e., as a higher-order derivative defined in terms of two derivatives: a given derivative and the Lie derivative. Being linear derivative, it has torsion and curvature tensor. These fields are computed in a general affine space from the corresponding general expressions of the generic derivative. Applications of the above considerations are discussed in a number of cases. Concerning the Lie derivative, it is been shown that the Poisson bracket is in fact a Lie derivative. Concerning the Fermi derivative, two applications are considered: (a) the explicit computation of the Fermi derivative in a general affine space and (b) the consideration of Freedman–Robertson–Walker spacetime endowed with a scalar torsion field, which satisfies the Cosmological Principle and the computation of Fermi derivative of the spatial directions defining a spatial frame along the cosmological fluid of comoving observers. It is found that torsion, even in this highly symmetric case, induces a kinematic rotation of the space axes, questioning the interpretation of torsion as a spin. Finally it is shown that the Lie derivative of the dynamical equations of an autonomous conservative dynamical system is equivalent to the standard Lie symmetry method. Full article
(This article belongs to the Special Issue Advances in Nonlinear Systems and Symmetry/Asymmetry)
16 pages, 457 KB  
Article
Approximation Properties of Chlodovsky-Type Two-Dimensional Bernstein Operators Based on (p, q)-Integers
by Ümit Karabıyık, Adem Ayık and Ali Karaisa
Symmetry 2024, 16(11), 1503; https://doi.org/10.3390/sym16111503 - 9 Nov 2024
Viewed by 1260
Abstract
In the present study, we introduce the two-dimensional Chlodovsky-type Bernstein operators based on the (p,q)-integer. By leveraging the inherent symmetry properties of (p,q)-integers, we examine the approximation properties of our new operator with [...] Read more.
In the present study, we introduce the two-dimensional Chlodovsky-type Bernstein operators based on the (p,q)-integer. By leveraging the inherent symmetry properties of (p,q)-integers, we examine the approximation properties of our new operator with the help of a Korovkin-type theorem. Further, we present the local approximation properties and establish the rates of convergence utilizing the modulus of continuity and the Lipschitz-type maximal function. Additionally, a Voronovskaja-type theorem is provided for these operators. We also investigate the weighted approximation properties and estimate the rate of convergence in the same space. Finally, illustrative graphics generated with Maple demonstrate the convergence rate of these operators to certain functions. The optimization of approximation speeds by these symmetric operators during system control provides significant improvements in stability and performance. Consequently, the control and modeling of dynamic systems become more efficient and effective through these symmetry-oriented innovative methods. These advancements in the fields of modeling fractional differential equations and control theory offer substantial benefits to both modeling and optimization processes, expanding the range of applications within these areas. Full article
(This article belongs to the Section Mathematics)
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13 pages, 266 KB  
Article
Some Estimates for Certain q-analogs of Gamma Integral Transform Operators
by Shrideh Al-Omari, Wael Salameh and Sharifah Alhazmi
Symmetry 2024, 16(10), 1368; https://doi.org/10.3390/sym16101368 - 15 Oct 2024
Viewed by 1255
Abstract
The aim of this work is to examine some q-analogs and differential properties of the gamma integral operator and its convolution products. The q-gamma integral operator is introduced in two versions in order to derive pertinent conclusions regarding the q-exponential [...] Read more.
The aim of this work is to examine some q-analogs and differential properties of the gamma integral operator and its convolution products. The q-gamma integral operator is introduced in two versions in order to derive pertinent conclusions regarding the q-exponential functions. Also, new findings on the q-trigonometric, q-sine, and q-cosine functions are extracted. In addition, novel results for first and second-order q-differential operators are established and extended to Heaviside unit step functions. Lastly, three crucial convolution products and extensive convolution theorems for the q-analogs are also provided. Full article
(This article belongs to the Special Issue Discussion of Properties and Applications of Integral Transform)
16 pages, 310 KB  
Article
On (p,q)-Analogs of the α-th Fractional Fourier Transform and Some (p,q)-Generalized Spaces
by Shrideh Al-Omari and Wael Salameh
Symmetry 2024, 16(10), 1307; https://doi.org/10.3390/sym16101307 - 3 Oct 2024
Viewed by 1508
Abstract
In this article, the (p,q)-analogs of the α-th fractional Fourier transform are provided, along with a discussion of their characteristics in specific classes of (p,q)-generalized functions. Two spaces of infinitely [...] Read more.
In this article, the (p,q)-analogs of the α-th fractional Fourier transform are provided, along with a discussion of their characteristics in specific classes of (p,q)-generalized functions. Two spaces of infinitely (p,q)-differentiable functions are defined by introducing two (p,q)-differential symmetric operators. The (p,q)-analogs of the α-th fractional Fourier transform are demonstrated to be continuous and linear between the spaces under discussion. Next, theorems pertaining to specific convolutions are established. This leads to the establishment of multiple symmetric identities, which in turn requires the construction of (p,q)-generalized spaces known as (p,q)-Boehmians. Finally, in addition to deriving the inversion formulas, the generalized (p,q)- analogs of the α-th fractional Fourier transform are introduced, and their general properties are discussed. Full article
12 pages, 264 KB  
Article
Notes on q-Gamma Operators and Their Extension to Classes of Generalized Distributions
by Shrideh Al-Omari, Wael Salameh and Sharifah Alhazmi
Symmetry 2024, 16(10), 1294; https://doi.org/10.3390/sym16101294 - 2 Oct 2024
Viewed by 1012
Abstract
This paper discusses definitions and properties of q-analogues of the gamma integral operator and its extension to classes of generalized distributions. It introduces q-convolution products, symmetric q-delta sequences and q-quotients of sequences, and establishes certain convolution theorems. The convolution [...] Read more.
This paper discusses definitions and properties of q-analogues of the gamma integral operator and its extension to classes of generalized distributions. It introduces q-convolution products, symmetric q-delta sequences and q-quotients of sequences, and establishes certain convolution theorems. The convolution theorems are utilized to accomplish q-equivalence classes of generalized distributions called q-Boehmians. Consequently, the q-gamma operators are therefore extended to the generalized spaces and performed to coincide with the classical integral operator. Further, the generalized q-gamma integral is shown to be linear, sequentially continuous and continuous with respect to some involved convergence equipped with the generalized spaces. Full article
(This article belongs to the Special Issue Discussion of Properties and Applications of Integral Transform)
17 pages, 301 KB  
Article
Sharp Results for a New Class of Analytic Functions Associated with the q-Differential Operator and the Symmetric Balloon-Shaped Domain
by Adeel Ahmad, Jianhua Gong, Akhter Rasheed, Saqib Hussain, Asad Ali and Zeinebou Cheikh
Symmetry 2024, 16(9), 1134; https://doi.org/10.3390/sym16091134 - 2 Sep 2024
Cited by 4 | Viewed by 1181
Abstract
In our current study, we apply differential subordination and quantum calculus to introduce and investigate a new class of analytic functions associated with the q-differential operator and the symmetric balloon-shaped domain. We obtain sharp results concerning the Maclaurin coefficients the second and third-order [...] Read more.
In our current study, we apply differential subordination and quantum calculus to introduce and investigate a new class of analytic functions associated with the q-differential operator and the symmetric balloon-shaped domain. We obtain sharp results concerning the Maclaurin coefficients the second and third-order Hankel determinants, the Zalcman conjecture, and its generalized conjecture for this newly defined class of q-starlike functions with respect to symmetric points. Full article
(This article belongs to the Special Issue Symmetry in Geometric Theory of Analytic Functions)
12 pages, 275 KB  
Article
Symmetric Identities Involving the Extended Degenerate Central Fubini Polynomials Arising from the Fermionic p-Adic Integral on p
by Maryam Salem Alatawi, Waseem Ahmad Khan and Ugur Duran
Axioms 2024, 13(7), 421; https://doi.org/10.3390/axioms13070421 - 22 Jun 2024
Cited by 1 | Viewed by 998
Abstract
Since the constructions of p-adic q-integrals, these integrals as well as particular cases have been used not only as integral representations of many special functions, polynomials, and numbers, but they also allow for deep examinations of many families of special numbers [...] Read more.
Since the constructions of p-adic q-integrals, these integrals as well as particular cases have been used not only as integral representations of many special functions, polynomials, and numbers, but they also allow for deep examinations of many families of special numbers and polynomials, such as central Fubini, Bernoulli, central Bell, and Changhee numbers and polynomials. One of the key applications of these integrals is for obtaining the symmetric identities of certain special polynomials. In this study, we focus on a novel generalization of degenerate central Fubini polynomials. First, we introduce two variable degenerate w-torsion central Fubini polynomials by means of their exponential generating function. Then, we provide a fermionic p-adic integral representation of these polynomials. Through this representation, we investigate several symmetric identities for these polynomials using special p-adic integral techniques. Also, using series manipulation methods, we obtain an identity of symmetry for the two variable degenerate w-torsion central Fubini polynomials. Finally, we provide a representation of the degenerate differential operator on the two variable degenerate w-torsion central Fubini polynomials related to the degenerate central factorial polynomials of the second kind. Full article
(This article belongs to the Special Issue Advanced Approximation Techniques and Their Applications, 2nd Edition)
13 pages, 307 KB  
Article
Sharp Estimates Involving a Generalized Symmetric Sălăgean q-Differential Operator for Harmonic Functions via Quantum Calculus
by Isra Al-Shbeil, Shahid Khan, Fairouz Tchier, Ferdous M. O. Tawfiq, Amani Shatarah and Adriana Cătaş
Symmetry 2023, 15(12), 2156; https://doi.org/10.3390/sym15122156 - 4 Dec 2023
Cited by 3 | Viewed by 1230
Abstract
In this study, we apply q-symmetric calculus operator theory and investigate a generalized symmetric Sălăgean q-differential operator for harmonic functions in an open unit disk. We consider a newly defined operator and establish new subclasses of harmonic functions in complex order. [...] Read more.
In this study, we apply q-symmetric calculus operator theory and investigate a generalized symmetric Sălăgean q-differential operator for harmonic functions in an open unit disk. We consider a newly defined operator and establish new subclasses of harmonic functions in complex order. We determine the sharp results, such as the sufficient necessary coefficient bounds, the extreme of closed convex hulls, and the distortion theorems for a new family of harmonic functions. Further, we illustrate how we connect the findings of previous studies and the results of this article. Full article
18 pages, 336 KB  
Article
Certain New Applications of Faber Polynomial Expansion for a New Class of bi-Univalent Functions Associated with Symmetric q-Calculus
by Chetan Swarup
Symmetry 2023, 15(7), 1407; https://doi.org/10.3390/sym15071407 - 13 Jul 2023
Viewed by 1145
Abstract
In this study, we applied the ideas of subordination and the symmetric q-difference operator and then defined the novel class of bi-univalent functions of complex order γ. We used the Faber polynomial expansion method to determine the upper bounds for the [...] Read more.
In this study, we applied the ideas of subordination and the symmetric q-difference operator and then defined the novel class of bi-univalent functions of complex order γ. We used the Faber polynomial expansion method to determine the upper bounds for the functions belonging to the newly defined class of complex order γ. For the functions in the newly specified class, we further obtained coefficient bounds ρ2 and the Fekete–Szegő problem ρ3ρ22, both of which have been restricted by gap series. We demonstrate many applications of the symmetric Sălăgean q-differential operator using the Faber polynomial expansion technique. The findings in this paper generalize those from previous studies. Full article
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