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Full-Text Articles in Physical Sciences and Mathematics

Existence Of Positive Periodic Solutions For A First-Order Semilinear Functional Differential Equation With An Iterative Source Term, Ahlème Bouakkaz, Rabah Khemis Mar 2026

Existence Of Positive Periodic Solutions For A First-Order Semilinear Functional Differential Equation With An Iterative Source Term, Ahlème Bouakkaz, Rabah Khemis

Turkish Journal of Mathematics

In this paper, we will establish the existence of positive periodic solutions for a class of first order iterative functional differential equations by using a powerful and effective technique based on the Krasnoselskii fixed point theorem together with some useful properties of a Green's function. The obtained results that complement some previous works, are illustrated with an example.


Simplicity In Le-Semigroups Via Partitions Of Full Words, And Its Applications To Regularity Conditions Induced By Linear Inequalities, Nareupanat Lekkoksung Mar 2026

Simplicity In Le-Semigroups Via Partitions Of Full Words, And Its Applications To Regularity Conditions Induced By Linear Inequalities, Nareupanat Lekkoksung

Turkish Journal of Mathematics

The concept of simplicity in le-semigroups has been used to characterize the coincidence of ideal elements and to study Khayopulu–Green’s relations. Several types of simplicities are known, including two-sided simplicity, left simplicity, right simplicity, bisimplicity, quasisimplicity, and biinterior simplicity. A natural question arises: are there further notions of simplicity for le-semigroups? If so, how are they related? By employing the notion of partition ideal elements, we observe that several potential simplicities have not yet been explored. In this paper, we introduce new forms of simplicity in le-semigroups defined via partitions of full words, and we investigate the …


On The Semigroups Of Order-Preserving And Orientation-Preserving Full Contraction Mappings On A Finite Chain, Gonca Ayik, Hayrullah Ayik Mar 2026

On The Semigroups Of Order-Preserving And Orientation-Preserving Full Contraction Mappings On A Finite Chain, Gonca Ayik, Hayrullah Ayik

Turkish Journal of Mathematics

Let OPCTn (OCTn) denote the semigroup consisting of all orientation-preserving (order-preserving) full contraction mappings on the finite chain Xn = {1 < ··· < n}, and let OPDCTn (ODCTn) denote the subsemigroup of OPCTn (OCTn) consisting of all order-decreasing transformations. The purpose of this paper is to determine the cardinalities of OPCTn, OPDCTn, N(ODCTn), and N(OPDCTn), and to identify generating sets of minimal size, thereby determining their ranks. Moreover, the number of idempotents of OPDCTn is determined.


A Geometric Property Characterizing The 3d-Generalized Clothoids, Pascual Lucas, José-Antonio Ortega-Yagües Mar 2026

A Geometric Property Characterizing The 3d-Generalized Clothoids, Pascual Lucas, José-Antonio Ortega-Yagües

Turkish Journal of Mathematics

In this paper, we study 3D-generalized clothoids, defined as curves for which there exists another distinct curve, with proportional arclength parameter, such that the Darboux lines of both curves at corresponding points are the same. We prove that these curves are those for which the ratio of torsion and curvature τ/κ is a linear rational function of the arclength. We also show that any 3D-generalized clothoid can be constructed from a rectifying curve, which is of constant curvature in the case of a 3D-clothoid.


Multiplicative Lorentz Matrix Multiplication And The Motion On Multiplicative Lorentz Plane, Osman Keçi̇li̇oğlu, İlayda Durmaz, Hali̇t Gündoğan Mar 2026

Multiplicative Lorentz Matrix Multiplication And The Motion On Multiplicative Lorentz Plane, Osman Keçi̇li̇oğlu, İlayda Durmaz, Hali̇t Gündoğan

Turkish Journal of Mathematics

In this paper, we define the multiplicative determinant for general n×n matrices, extending previous studies that were limited to lower-dimensional cases. Additionally, we introduce a novel matrix multiplication operation based on the multiplicative Lorentz inner product and conduct a thorough investigation of its algebraic properties. Furthermore, we explore rotational and reflectional transformations in the two-dimensional multiplicative Lorentz space L*2, supported by illustrative examples of these geometric motions.


Investigation Of The Behavior Of Biparametric Potentials Associated With The Laplace-Bessel Differential Operator In Weighted Lebesgue Spaces, Çağla Seki̇n Mar 2026

Investigation Of The Behavior Of Biparametric Potentials Associated With The Laplace-Bessel Differential Operator In Weighted Lebesgue Spaces, Çağla Seki̇n

Turkish Journal of Mathematics

In this article, we investigate the mapping properties of potential-type operators of the form Jαβ = (E + (−Δν)β/2)−α/β, (β, α > 0), where Δν is the Laplace-Bessel differential operator. We establish norm inequalities that describe the boundedness of the operator Jαβ from Lp,ν to Lq,ν under suitable conditions on α, β, p and q. The results extend and unify the known estimates for classical potential operators. In particular, the cases β = 1 and β = 2 correspond to the modified Flett and Bessel potentials, respectively.


On Fredholm Type Integral Equations In H\"{O}Der Spaces: Existence Of Solutions, Yasemi̇n Başci, Adi̇l Misir, Süleyman Öğrekçi̇ Mar 2026

On Fredholm Type Integral Equations In H\"{O}Der Spaces: Existence Of Solutions, Yasemi̇n Başci, Adi̇l Misir, Süleyman Öğrekçi̇

Turkish Journal of Mathematics

In this study, we investigate the existence of solutions for a quadratic integral equation of the Fredholm type. The analysis is conducted on a finite interval bounded by two arbitrary constants, where the unknown function is associated with a prescribed kernel and two operators satisfying specific regularity and boundedness conditions. The methodological framework of this work is built upon the classical Schauder fixed point theorem, complemented by the structural properties of Hölder spaces. The results obtained not only encompass but also extend several previous contributions in the literature, as the discussion is carried out within a generalized setting over the …


Exploring Topological And Game-Theoretic Properties Of Selective Covering Bispaces, Selma Özçağ Mar 2026

Exploring Topological And Game-Theoretic Properties Of Selective Covering Bispaces, Selma Özçağ

Turkish Journal of Mathematics

This paper considers set selectively star countable chain condition in a bitopological setting, exploring its fundamental topological properties and its relationships with the existing selective covering properties. Furthermore we investigate a game-theoretic characterizations of the selectively countable chain condition property in bitopological spaces.


The Killing Magnetic Curves In The Anti-De Sitter Space H31, Uğur Dursun Mar 2026

The Killing Magnetic Curves In The Anti-De Sitter Space H31, Uğur Dursun

Turkish Journal of Mathematics

In this paper, we study space-like, time-like and light-like Killing magnetic curves derived from Killing magnetic vector fields of the anti-de Sitter space H31 by using the half-space model H31 of H31. We find the first integrals of the system of nonlinear differential equations that describe the Killing magnetic curves corresponding to some Killing vector fields of H31, and then we give some particular solutions to obtain space-like, time-like and light-like magnetic curves of H31. Also, we calculate the curvature and torsion of some space-like and time-like …


A Non-Newtonian Approach To Screw Motion And Dual Numbers, Esra Parlak, Zehra Özdemi̇r Mar 2026

A Non-Newtonian Approach To Screw Motion And Dual Numbers, Esra Parlak, Zehra Özdemi̇r

Turkish Journal of Mathematics

In this paper, we define multiplicative dual numbers, multiplicative dual vectors, scalars, and vector products associated with the multiplicative dual numbers. We give the base elements of multiplicative dual elliptic quaternions and their operational properties. We explain the rotation and translation motions in multiplicative dual elliptical quaternions. We provide the matrix representations of the screw motion using multiplicative dual elliptical quaternions. Thanks to these multiplicative dual elliptical quaternions, we explain the screw motion along with rotation and translation with theorems and proofs. We visualize this screw motion with mathematical programs by applying screw-ruled surfaces.


Cover And Contents Mar 2026

Cover And Contents

Turkish Journal of Mathematics

No abstract provided.


3-Graded Cartan Calculus On 𝒪(ℂQ1|1|1), Sultan Çeli̇k, Sali̇h Çeli̇k Jan 2026

ℤ3-Graded Cartan Calculus On 𝒪(ℂQ1|1|1), Sultan Çeli̇k, Sali̇h Çeli̇k

Turkish Journal of Mathematics

After a brief introduction of the basic concepts of ℤ3-grading, the paper continues by introducing ℤ3-graded differential calculus and ℤ3-graded Cartan calculus. Then, using a matrix R which is a solution of the Yang-Baxter equation, a new ℤ3-graded quantum group and a ℤ3-graded quantum space are introduced. The scheme of the ℤ3-graded differential calculus developed on the algebra of functions on this quantum space is extended to the ℤ3-graded Cartan calculus and all the results obtained are formulated using the matrix R.


G-Topological Groupoids, Osman Mucuk Jan 2026

G-Topological Groupoids, Osman Mucuk

Turkish Journal of Mathematics

In the groupoid theory, it is unclear that a topological groupoid's quotient groupoid with the quotient topology is topological.  In this paper, we approach this problem considering  G-methods and G-convergence. We define  G-topological groupoid, which agrees with the sequential version of a topological groupoid in the particular case G=lim, and give some counterexamples. Then, we extend the usual properties of topological groupoids to the G-topological groupoids. We also prove that a G-topological groupoid's quotient groupoid is  G-topological groupoid when a normal subgroupoid is suitably chosen. This result enables us to obtain examples of topological quotient groupoids in a particular case.


The Derivative Of Spectral Function Of The Problem With The Boundary Condition Dependent On Spectral Parameter, Eli̇f Başkaya, Haskiz Coşkun Jan 2026

The Derivative Of Spectral Function Of The Problem With The Boundary Condition Dependent On Spectral Parameter, Eli̇f Başkaya, Haskiz Coşkun

Turkish Journal of Mathematics

In this study, the computation of the derivative of the spectral function for Sturm-Liouville problem with eigenvalue dependent boundary condition at the finite left end is considered.


The Variation Of Eigenvalues Of The Two-Dimensional Magnetic Schrödinger Operator With Respect To The Angle Of A Flat Sector, Araz R. Aliev, Elshad H. Eyvazov Jan 2026

The Variation Of Eigenvalues Of The Two-Dimensional Magnetic Schrödinger Operator With Respect To The Angle Of A Flat Sector, Araz R. Aliev, Elshad H. Eyvazov

Turkish Journal of Mathematics

A two-dimensional Schrödinger operator with a spherically symmetric electric potential and an Aharonov Bohm magnetic field in a circular sector under Neumann boundary conditions is considered. The intervals of the angular variation of the flat region are found, where the eigenvalues of the Neumann problem for the Schrödinger operator with a spherically symmetric electric potential strictly decrease monotonically in the Aharonov-Bohm magnetic field.


Further Geometric Properties Of The Generalized K-Bessel Functions, Merve Görgülü, İbrahi̇m Aktaş Jan 2026

Further Geometric Properties Of The Generalized K-Bessel Functions, Merve Görgülü, İbrahi̇m Aktaş

Turkish Journal of Mathematics

This study investigates certain geometric properties of the normalized k-Bessel function, which is a natural generalization of classical and modified Bessel functions of the first kind. These geometric properties include η-starlikeness, η-uniform convexity, starlikeness associated with exponential function and Bernoulli’s lemniscate, and convexity associated with exponential function and Bernoulli’s lemniscate. Moreover, certain corollaries related to classical and modified Bessel functions are presented by specialising parameters. In addition, some examples and their graphical representations are provided to support the findings of this study.


Cover And Contents Jan 2026

Cover And Contents

Turkish Journal of Mathematics

No abstract provided.


Some Methods For Finding The Number Of Partitions Of N With M−Parts, P(N, M), Yusuf Soyvural, Ali̇ Bülent Eki̇n Jan 2026

Some Methods For Finding The Number Of Partitions Of N With M−Parts, P(N, M), Yusuf Soyvural, Ali̇ Bülent Eki̇n

Turkish Journal of Mathematics

P(n, m) denotes the number of partitions of n with m parts, while Pm(n) denotes the number of partitions of n with parts at most m. It is a well-known result that the number of partitions of n ≥ 0 into m or fewer parts is equal to Pm(n). In the literature, there are some results for P(n, m) and Pm(n) for some values of m. In this work, we give more compact results for P(n …


Representation Of Inverse Ordered Semigroups By Means Of Symmetric Inverse Semigroups On A Set, Michael Tsingelis Jan 2026

Representation Of Inverse Ordered Semigroups By Means Of Symmetric Inverse Semigroups On A Set, Michael Tsingelis

Turkish Journal of Mathematics

A partial one-to-one mapping on a set X is a mapping whose domain is a subset of X. The set of partial one-one mappings on a set X is an inverse semigroup (the symmetric inverse semigroup on X). An element x of an ordered semigroup (S, ·, ≤) is called an inverse element of α ∈ S if α ≤ xαx and xxαx. An inverse ordered semigroup is an ordered semigroup S for which every element of S possesses an inverse element and the inverse elements of any element of S are in …


Fubini Collocation Method For Numerical Solutions Of Differential Equations With Quadratic And Cubic Nonlinearities, Kübra Erdem Bi̇çer, Havva Türkhan Jan 2026

Fubini Collocation Method For Numerical Solutions Of Differential Equations With Quadratic And Cubic Nonlinearities, Kübra Erdem Bi̇çer, Havva Türkhan

Turkish Journal of Mathematics

In this study, the Fubini collocation method is proposed for the approximate solution of nonlinear differential equations. The method utilizes fundamental relations involving Fubini polynomials and their derivatives, employing collocation points to enhance solution accuracy. Within this framework, the given differential equation is transformed into a system of nonlinear algebraic equations involving the unknown coefficients of the approximate solution. This resulting system is then solved using appropriate numerical techniques to obtain the approximate solution. The effectiveness of the proposed method is demonstrated through several test problems, with accuracy evaluated using absolute error functions. Furthermore, illustrative examples and residual-based error analysis …


Cospectrality Results For Signed Graphs With Two Eigenvalues Unequal To ±1, Willem H. Haemers, Hati̇ce Topcu Jan 2026

Cospectrality Results For Signed Graphs With Two Eigenvalues Unequal To ±1, Willem H. Haemers, Hati̇ce Topcu

Turkish Journal of Mathematics

Recently the collection G of all signed graphs for which the adjacency matrix has all but at most two eigenvalues equal to ±1 has been determined. Here we investigate G for cospectral pairs, and for signed graphs determined by their spectrum (up to switching). If the order is at most 20, the outcome is presented in a clear table. If the spectrum is symmetric we find all signed graphs in G determined by their spectrum, and we obtain all signed graphs cospectral with the bipartite double of the complete graph. In addition we determine all signed graphs cospectral with the …


Codazzi Normalized Null Hypersurfaces, Théophile Kemajou Mbiakop, Cyriaque Atindogbe, Ferdinand Ngakeu Jan 2026

Codazzi Normalized Null Hypersurfaces, Théophile Kemajou Mbiakop, Cyriaque Atindogbe, Ferdinand Ngakeu

Turkish Journal of Mathematics

We introduce a class of null hypersurfaces of Lorentzian manifolds, namely Codazzi normalized null hyper surfaces, whose (screen) shape operator associated with the rigged vector field is a Codazzi tensor. Several examples are given to support our study. Moreover, we investigate conditions implying that the induced Riemannian screen structure on a Codazzi-type normalized null hypersurface of a Lorentzian space is locally a nontrivial warped product.


On Almost Kenmotsu Manifolds Admitting Nearly Vacuum Static Equations With Applications, Uday Chand De, Krishnendu De, Sudhakar Kumar Chaubey Jan 2026

On Almost Kenmotsu Manifolds Admitting Nearly Vacuum Static Equations With Applications, Uday Chand De, Krishnendu De, Sudhakar Kumar Chaubey

Turkish Journal of Mathematics

In this article, we study certain characteristics of nearly vacuum static equations on almost Kenmotsu manifolds. It is established that an η-Einstein almost Kenmotsu manifold allowing nearly vacuum static equations is of constant scalar curvature and either the solution is trivial or, the manifold reduces to an Einstein manifold. Next,  nearly vacuum static equations on (κ,μ)-almost Kenmotsu manifolds and generalized (κ,μ)'-nullity distribution are considered and we obtain several interesting results. Moreover, we illustrate that if a 3-dimensional Kenmotsu manifold allows nearly vacuum static equations, then the manifold is locally isometric to the hyperbolic space Η3(-1). After that, we investigate a …


On The Existence Of Solutions For Nonlinear Third-Order Q-Difference Equations With Boundary Conditions Involving Q-Integrals, İlker Gençtürk Nov 2025

On The Existence Of Solutions For Nonlinear Third-Order Q-Difference Equations With Boundary Conditions Involving Q-Integrals, İlker Gençtürk

Turkish Journal of Mathematics

In this research, we focus on investigating the existence of solutions for a q-integral boundary value problem associated with third-order nonlinear q-difference equations. To achieve this, we employ two fundamental mathematical tools: the Banach contraction principle and Krasnoselskii’s fixed point theorem, which provide the theoretical framework for our analysis. Furthermore, to illustrate the applicability and robustness of our results, we present and discuss several concrete examples that highlight the practical implications of the proposed methods.


Classifications Of Gradient Almost Ricci Solitons Within The Framework Of Closed Conformal Vector Fields, Akram Ali, Fatemah Mofarreh, Jae Won Lee Nov 2025

Classifications Of Gradient Almost Ricci Solitons Within The Framework Of Closed Conformal Vector Fields, Akram Ali, Fatemah Mofarreh, Jae Won Lee

Turkish Journal of Mathematics

In this paper, we consider gradient almost Ricci solitons with nonparallel closed conformal vector fields. We classify gradient almost Ricci solitons and show that a complete, noncompact gradient almost Ricci soliton admitting a nonparallel closed conformal vector field, is locally a warped product with Einstein fibers, while in the second case, under additional hypothesis, gradient almost Ricci soliton is totally umbilical if and only if it has constant scalar curvature.


On Trinomial Units Of The Group Ring RcN, César A. Hernandez Melo, Fernanda Diniz De Melo Hernandez, Patricia Massae Kitani Nov 2025

On Trinomial Units Of The Group Ring RcN, César A. Hernandez Melo, Fernanda Diniz De Melo Hernandez, Patricia Massae Kitani

Turkish Journal of Mathematics

Let R be an associative ring with identity, Cn be the cyclic group of order n, and g be a generator of Cn. In this manuscript, for iN such that 1 ≤ i < n and gcd(i, n) = 1, the algebraic properties of the trinomial elements hi = -1 + g + g-i in the group ring RCn are investigated. More precisely, necessary and sufficient conditions are given for an element hi to be a unit in RCn. When hi is a unit, explicit formulas for computing …


End-Regular Flower Graphs CR,S, Joerg Koppitz, Suparat Phantukang, Phurinut Srisawad, Somnuek Worawiset Nov 2025

End-Regular Flower Graphs CR,S, Joerg Koppitz, Suparat Phantukang, Phurinut Srisawad, Somnuek Worawiset

Turkish Journal of Mathematics

In the present paper, we study the regularity of the endomorphism monoid of a class of graphs, which generalizes the cycle graph. We give a complete list of all end-regular r × s flower graphs. In particular, for an odd integer s ≥ 3, the s × s flower graph Cs,s has a regular endomorphism monoid, i.e., Cs,s is end-regular. For Cs,s, s ≥ 3 odd, we determine the cardinality and the rank of its endomorphism monoid (including a generating set of minimal size).


Generalized Szász–Mirakyan Operators In The Variation Seminorm, Sare Yumruçali, Harun Karsli, Fatma Taşdelen Yeşi̇ldal Nov 2025

Generalized Szász–Mirakyan Operators In The Variation Seminorm, Sare Yumruçali, Harun Karsli, Fatma Taşdelen Yeşi̇ldal

Turkish Journal of Mathematics

The aim of the present paper is to introduce generalized Szász–Mirakyan operators. This article studies the property of variation seminorm and some approximation properties of generalized Szász–Mirakyan operators not only in normed spaces but also in variation seminorm. We obtain convergence properties of our operators using of Korovkin’s theorem and the order of convergence by using a classical approach, the second modulus of continuity and Peetre’s K functional. We also give asymptotic formula and the convergence of the derivatives for these operators. We investigate the variation detracting property of generalized Szász–Mirakyan operators. We show the convergence of generalized Szász–Mirakyan operators …


Some Properties Of Nabla Laplace Transform On Isolated Time Scales, Müfi̇t Şan, Huri̇ye Dağ, Manuel D. Ortigueira Nov 2025

Some Properties Of Nabla Laplace Transform On Isolated Time Scales, Müfi̇t Şan, Huri̇ye Dağ, Manuel D. Ortigueira

Turkish Journal of Mathematics

This study presents the properties of the bilateral and unilateral nabla Laplace transform, defined on isolated time scales. Furthermore, it explores the nabla Laplace transforms of several elementary functions, employing various proof techniques from real and complex analysis. The findings are illustrated with examples, demonstrating the applicability of these definitions.


From Rough Categories To Rough Groupoids, Mehmet Mustafa Beydaği, Abdullah Fati̇h Özcan, İlhan İçen Nov 2025

From Rough Categories To Rough Groupoids, Mehmet Mustafa Beydaği, Abdullah Fati̇h Özcan, İlhan İçen

Turkish Journal of Mathematics

In this study, we introduce the concepts of rough category and rough groupoid by combining the concepts of category theory and groupoid with rough set theory. We present some properties and examples of these concepts, which are discussed for the first time. Additionally, by defining a rough functor among the rough categories, the category of rough categories were created. Moreover, rough groupoid homomorphism, rough action groupoid, and category of the rough groupoids have been examined algebraically and introduced to the literature.