Hatun Ozlem Guney

Current Organizations / Institutes

The organizations/institutes from the scholar's latest article

Dicle University

Research Subjects

Functional Analysis

Research Interests

Hatun Ozlem Guney has a total of 27 co-authors. Here are the top co-authors by number of shared publications:

Shigeyoshi Owa
“1 Decembrie 1918” University Alba Iulia, 510009 Alba-Iulia, Romania
14 shared publications
Gangadharan Murugusundaramoorthy
Department of Mathematics, School of Advanced sciences, Vellore Institute of Technology, Vellore, India
13 shared publications
Kaliyappan Vijaya
Department of Mathematics, School of Advanced sciences, Vellore Institute of Technology, Vellore, India
7 shared publications
Daniel Breaz
Department of Mathematics, “1 Decembrie 1918” University of Alba Iulia, 510009 Alba Iulia, Romania
5 shared publications
Fethiye Müge Sakar
Department of Management, Dicle University, 21280 Diyarbakir, Turkey
3 shared publications
Janusz Sokół
Faculty of Exact and Technical Sciences, University of Rzeszów, Rzeszów, Poland
3 shared publications

Latest Publications

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- 10 August 2026
- Published by Springer Nature in Afrika Matematika
Some bounds for a generalized subclass of bounded turning functions defined by a new differential-difference operator
by Seda Karadeniz, Hatun Özlem Güney
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- 10 August 2026
- Published by Springer Nature in Afrika Matematika
Some bounds for a generalized subclass of bounded turning functions defined by a new differential-difference operator
by Seda Karadeniz, Hatun Özlem Güney
Open Access
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- 3 April 2026
- Published by MDPI AG in Mathematics
Coefficient Bounds for New Subclass of Starlike Functions with Respect to Symmetric Points Associated with an Epicycloid
by Büşra Körfeci, Hatun Özlem Güney
This paper presents a new subclass ${BS}_{k - 1}^{*}$ of starlike functions with respect to symmetric points associated with a domain bounded by an epicycloid with $k - 1$ cusps. First, we derive bounds for the first five Taylor coefficients of functions in this subclass and obtain the first three coefficients of the corresponding logarithmic function. Moreover, for some special values, upper and lower bounds are established for several important functionals and determinants associated with the coefficients of functions in this subclass.
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- 3 April 2026
- Published by MDPI AG in Mathematics
Open Access
Coefficient Bounds for New Subclass of Starlike Functions with Respect to Symmetric Points Associated with an Epicycloid
by Büşra Körfeci, Hatun Özlem Güney
This paper presents a new subclass ${BS}_{k - 1}^{*}$ of starlike functions with respect to symmetric points associated with a domain bounded by an epicycloid with $k - 1$ cusps. First, we derive bounds for the first five Taylor coefficients of functions in this subclass and obtain the first three coefficients of the corresponding logarithmic function. Moreover, for some special values, upper and lower bounds are established for several important functionals and determinants associated with the coefficients of functions in this subclass.
Open Access
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- 30 March 2026
- Published by RGN Publications in Communications in Mathematics and Applications
New Application of Libera Integral Operator
by Muhammet Kamali, Hatun Özlem Guney, Shigeyoshi Owa
In this paper, we introduce the new subclass $A_{j}(n, \alpha, \beta)$ of $A(n)$ using $Lf(z)$. Some interesting properties of functions $f(z) \in A(n)$ are studied with illustrative examples.
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- 30 March 2026
- Published by RGN Publications in Communications in Mathematics and Applications
Open Access
New Application of Libera Integral Operator
by Muhammet Kamali, Hatun Özlem Guney, Shigeyoshi Owa
In this paper, we introduce the new subclass $A_{j}(n, \alpha, \beta)$ of $A(n)$ using $Lf(z)$. Some interesting properties of functions $f(z) \in A(n)$ are studied with illustrative examples.
Open Access
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- 23 September 2025
- Published by Communications Faculty of Sciences University of Ankara Series A1 Mathematics and Statistics in Communications Faculty of Sciences University of Ankara Series A1 Mathematics and Statistics
Generalization properties of Bernardi integral operator
by Muhammet Kamali, Hatun Özlem Guney, Shigeyoshi Owa
Let $A\left( n\right)$ be the class of analytic functions $f\left(z\right)$ of the form \begin{equation*} f\left( z\right) =z+\sum_{k=n}^{\infty }a_{k}z^{k},\;\;\left( n=2,3,4,...\right) \end{equation*} in the open unit disk $U.$ We introduce the integral operator $B_{j}f\left( z\right) $$=B\left( B_{j-1}f\left( z\right) \right) $, $B_{1}f\left( z\right) =Bf\left( z\right)$ and $B_{0}f\left( z\right) =f\left( z\right) $. In the present paper, we define the subclass $M_{j}\left( n,\gamma ,\alpha \right) $ and discuss some interesting properties of $f\left( z\right) \in A\left( n\right)$ concerning with the class $M_{j}\left( n,\gamma ,\alpha \right) .$
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- 23 September 2025
- Published by Communications Faculty of Sciences University of Ankara Series A1 Mathematics and Statistics in Communications Faculty of Sciences University of Ankara Series A1 Mathematics and Statistics
Open Access
Generalization properties of Bernardi integral operator
by Muhammet Kamali, Hatun Özlem Guney, Shigeyoshi Owa
Let $A\left( n\right)$ be the class of analytic functions $f\left(z\right)$ of the form \begin{equation*} f\left( z\right) =z+\sum_{k=n}^{\infty }a_{k}z^{k},\;\;\left( n=2,3,4,...\right) \end{equation*} in the open unit disk $U.$ We introduce the integral operator $B_{j}f\left( z\right) $$=B\left( B_{j-1}f\left( z\right) \right) $, $B_{1}f\left( z\right) =Bf\left( z\right)$ and $B_{0}f\left( z\right) =f\left( z\right) $. In the present paper, we define the subclass $M_{j}\left( n,\gamma ,\alpha \right) $ and discuss some interesting properties of $f\left( z\right) \in A\left( n\right)$ concerning with the class $M_{j}\left( n,\gamma ,\alpha \right) .$
Open Access
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- 5 August 2025
- Published by MDPI AG in Axioms
New Class of Specific Functions with Fractional Derivatives
by Hatun Özlem Güney, Shigeyoshi Owa
Let $A_{n}$ be the class of specific analytic functions $f (z) = z + \sum_{k = 1}^{\infty} a_{1 + \frac{k}{n}} z^{1 + \frac{k}{n}} (n \in N = {1, 2, 3, \dots})$ in the open unit disk $U .$ For $f (z) \in A_{n},$ fractional derivatives $D_{z}^{λ} f (z)$ and $D_{z}^{j + λ} f (z)$ $(0 \leq λ < 1, j \in N)$ are defined by using Gamma functions. Applying such fractional derivatives, we introduce a new subclass $A_{n} (j, λ, α, β)$ of $A_{n} .$ In this paper, we establish sufficient conditions for $f (z)$ for $A_{n} (j, λ, α, β),$ coefficient inequalities for $| a_{1 + \frac{1}{n}} |$ and $| a_{1 + \frac{k}{n}} |$ $(k = 2, 3, 4, \dots)$ of $f (z) \in A_{n} (j, λ, α, β),$ and some interesting argument properties of fractional derivatives for $f (z) \in A_{n}$ through an example.
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- 5 August 2025
- Published by MDPI AG in Axioms
Open Access
New Class of Specific Functions with Fractional Derivatives
by Hatun Özlem Güney, Shigeyoshi Owa
Let $A_{n}$ be the class of specific analytic functions $f (z) = z + \sum_{k = 1}^{\infty} a_{1 + \frac{k}{n}} z^{1 + \frac{k}{n}} (n \in N = {1, 2, 3, \dots})$ in the open unit disk $U .$ For $f (z) \in A_{n},$ fractional derivatives $D_{z}^{λ} f (z)$ and $D_{z}^{j + λ} f (z)$ $(0 \leq λ < 1, j \in N)$ are defined by using Gamma functions. Applying such fractional derivatives, we introduce a new subclass $A_{n} (j, λ, α, β)$ of $A_{n} .$ In this paper, we establish sufficient conditions for $f (z)$ for $A_{n} (j, λ, α, β),$ coefficient inequalities for $| a_{1 + \frac{1}{n}} |$ and $| a_{1 + \frac{k}{n}} |$ $(k = 2, 3, 4, \dots)$ of $f (z) \in A_{n} (j, λ, α, β),$ and some interesting argument properties of fractional derivatives for $f (z) \in A_{n}$ through an example.
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- 18 April 2025
- Published by Springer Nature in Afrika Matematika
Universally prestarlike functions associated with generalized telephone numbers
by G. Murugusundaramoorthy, H. Ö. Güney
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- 18 April 2025
- Published by Springer Nature in Afrika Matematika
Universally prestarlike functions associated with generalized telephone numbers
by G. Murugusundaramoorthy, H. Ö. Güney
Open Access
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Cited by 2
- 17 February 2025
- Published by Springer Nature in Afrika Matematika
New sufficient conditions for p-valent functions
by Hatun Özlem Güney, Sevtap Sümer, Shigeyoshi Owa
Let $$\mathcal {A}_{p}$$ $A_{p}$ be the class of functions f(z) of the form $$ f(z)=z^{p}+a_{p+1}z^{p+1}+a_{p+2}z^{p+2}+\cdots , (p\in \mathbb {N}=\{1,2,3,\ldots \}) $$ $f (z) = z^{p} + a_{p + 1} z^{p + 1} + a_{p + 2} z^{p + 2} + \dots, (p \in N = {1, 2, 3, \dots})$ that are analytic in the open unit disc $$\mathbb {U}=\big \{ z\in \mathbb {C}: |z| <1\big \}$$ $U = {z \in C : | z | < 1}$ . For $$f(z)\in \mathcal {A}_{p}$$ $f (z) \in A_{p}$ , Nunokawa considered some conditions such that f(z) is $$p-$$ $p -$ valent in $$\mathbb {U}$$ $U$ . Applying the results by Nunokawa, we discuss some interesting properties for functions $$f(z)\in \mathcal {A}_{p}$$ $f (z) \in A_{p}$ . Also, we give some examples for our results.
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- 17 February 2025
- Published by Springer Nature in Afrika Matematika
Open Access
New sufficient conditions for p-valent functions
by Hatun Özlem Güney, Sevtap Sümer, Shigeyoshi Owa
Let $$\mathcal {A}_{p}$$ $A_{p}$ be the class of functions f(z) of the form $$ f(z)=z^{p}+a_{p+1}z^{p+1}+a_{p+2}z^{p+2}+\cdots , (p\in \mathbb {N}=\{1,2,3,\ldots \}) $$ $f (z) = z^{p} + a_{p + 1} z^{p + 1} + a_{p + 2} z^{p + 2} + \dots, (p \in N = {1, 2, 3, \dots})$ that are analytic in the open unit disc $$\mathbb {U}=\big \{ z\in \mathbb {C}: |z| <1\big \}$$ $U = {z \in C : | z | < 1}$ . For $$f(z)\in \mathcal {A}_{p}$$ $f (z) \in A_{p}$ , Nunokawa considered some conditions such that f(z) is $$p-$$ $p -$ valent in $$\mathbb {U}$$ $U$ . Applying the results by Nunokawa, we discuss some interesting properties for functions $$f(z)\in \mathcal {A}_{p}$$ $f (z) \in A_{p}$ . Also, we give some examples for our results.
Cited by 2
Open Access
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Cited by 10
- 28 December 2024
- Published by Hacettepe University in Hacettepe Journal of Mathematics and Statistics
Introduction in third-order fuzzy differential subordination
by Georgia Irina Oros, Gheorghe Oros, Özlem Güney
In light of the well-established and widely-used theory of differential subordination, recent works incorporating fuzzy elements into Geometric Function Theory have given rise to the concept of fuzzy differential subordination. Second-order fuzzy differential subordinations were taken into consideration for studies up until this point. The research described in this paper aims to expand the concept of fuzzy differential subordination to third-order fuzzy differential subordination, building on an idea first put forth in 2011 by Jos\'{e} A. Antonino and Sanford S. Miller and still being investigated by scholars today. The key concepts and preliminary findings required for the development of this branch of fuzzy differential subordination are introduced. The class of admissible functions is specified, the fundamental theorems are established and the fundamental concepts of the third-order fuzzy subordination approach are presented. Several examples constructed as applications of the new results demonstrate the applicability of the new findings.
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- 28 December 2024
- Published by Hacettepe University in Hacettepe Journal of Mathematics and Statistics
Open Access
Introduction in third-order fuzzy differential subordination
by Georgia Irina Oros, Gheorghe Oros, Özlem Güney
In light of the well-established and widely-used theory of differential subordination, recent works incorporating fuzzy elements into Geometric Function Theory have given rise to the concept of fuzzy differential subordination. Second-order fuzzy differential subordinations were taken into consideration for studies up until this point. The research described in this paper aims to expand the concept of fuzzy differential subordination to third-order fuzzy differential subordination, building on an idea first put forth in 2011 by Jos\'{e} A. Antonino and Sanford S. Miller and still being investigated by scholars today. The key concepts and preliminary findings required for the development of this branch of fuzzy differential subordination are introduced. The class of admissible functions is specified, the fundamental theorems are established and the fundamental concepts of the third-order fuzzy subordination approach are presented. Several examples constructed as applications of the new results demonstrate the applicability of the new findings.
Cited by 10
Open Access
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- 9 May 2024
- Published by MDPI AG in Mathematics
New Properties of Analytic Functions
by Hatun Özlem Güney, Shigeyoshi Owa
In the present paper, we consider the class $\bar{A}$ of functions $f (z)$ of the form $f (z) = z + \sum_{k = 1}^{\infty} a_{1 + \frac{k}{3}} z^{1 + \frac{k}{3}}$ that are analytic in the open unit disc $U .$ If $a_{1 + \frac{k}{3}} = 0$ for $k \neq 3 n$ $(n = 1, 2, 3, \dots),$ then $f (z)$ is given by $f (z) = z + \sum_{k = 2}^{\infty} a_{k} z^{k} .$ For such functions $f (z) \in \bar{A},$ some interesting properties for subordinations and strongly starlike functions are given. Also, some interesting examples for the results are shown.
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- 9 May 2024
- Published by MDPI AG in Mathematics
Open Access
New Properties of Analytic Functions
by Hatun Özlem Güney, Shigeyoshi Owa
In the present paper, we consider the class $\bar{A}$ of functions $f (z)$ of the form $f (z) = z + \sum_{k = 1}^{\infty} a_{1 + \frac{k}{3}} z^{1 + \frac{k}{3}}$ that are analytic in the open unit disc $U .$ If $a_{1 + \frac{k}{3}} = 0$ for $k \neq 3 n$ $(n = 1, 2, 3, \dots),$ then $f (z)$ is given by $f (z) = z + \sum_{k = 2}^{\infty} a_{k} z^{k} .$ For such functions $f (z) \in \bar{A},$ some interesting properties for subordinations and strongly starlike functions are given. Also, some interesting examples for the results are shown.
Open Access
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Cited by 5
- 8 March 2024
- Published by MDPI AG in Mathematics
Starlike Functions of the Miller–Ross-Type Poisson Distribution in the Janowski Domain
by Gangadharan Murugusundaramoorthy, Hatun Özlem Güney, Daniel Breaz
In this paper, considering the various important applications of Miller–Ross functions in the fields of applied sciences, we introduced a new class of analytic functions $f,$ utilizing the concept of Miller–Ross functions in the region of the Janowski domain. Furthermore, we obtained initial coefficients of Taylor series expansion of $f,$ coefficient inequalities for $f^{- 1}$ and the Fekete–Szegö problem. We also covered some key geometric properties for functions f in this newly formed class, such as the necessary and sufficient condition, convex combination, sequential subordination and partial sum findings.
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- 8 March 2024
- Published by MDPI AG in Mathematics
Open Access
Starlike Functions of the Miller–Ross-Type Poisson Distribution in the Janowski Domain
by Gangadharan Murugusundaramoorthy, Hatun Özlem Güney, Daniel Breaz
In this paper, considering the various important applications of Miller–Ross functions in the fields of applied sciences, we introduced a new class of analytic functions $f,$ utilizing the concept of Miller–Ross functions in the region of the Janowski domain. Furthermore, we obtained initial coefficients of Taylor series expansion of $f,$ coefficient inequalities for $f^{- 1}$ and the Fekete–Szegö problem. We also covered some key geometric properties for functions f in this newly formed class, such as the necessary and sufficient condition, convex combination, sequential subordination and partial sum findings.
Cited by 5

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