https://kkms.org/index.php/kjm/issue/feed Korean Journal of Mathematics 2024-06-30T19:03:07+09:00 Cho, Dong Hyun kjmeditor@kangwon.ac.kr Open Journal Systems <p class="p1"><span class="s1"><strong>About this Journal</strong></span></p> <p class="p1"><span class="s1">The Korean Journal of Mathematics (KJM) is the official journal of The Kangwon-Kyungki Mathematical Society (KKMS). Abbreviated title is "Korean J. Math.". This journal was launched in 1993. One volume is published each year, and each volume consists of four issues (March 30th, June 30th, September 30th, December 30th).</span></p> <p class="p1"> </p> <p class="p2"><span class="s2"><a href="http://kkms.org/index.php/kjm/about/editorialTeam"><strong>Editorial Board</strong></a></span></p> <p class="p1"> </p> <p class="p1"><span class="s1"><strong>Bibliographic Information</strong></span></p> <p class="p1"><span class="s1">pISSN: 1976-8605 (Print)<br />eISSN: 2288-1433 (Online)<br />doi: 10.11568/kjm</span></p> <p class="p1"> </p> <p class="p3"><span class="s1"><strong>Indexing and Abstracting Service</strong></span></p> <p class="p1"><span class="s1">Articles published in this journal are indexed on abstracted in Korea Citation Index (KCI), Mathematical Reviews, zbMath, Emerging Sources Citation Index (ESCI), and Scopus. </span></p> https://kkms.org/index.php/kjm/article/view/1640 Fuzzy lattice ordered group based on fuzzy partial ordering relation 2024-04-14T12:10:26+09:00 Sileshe Gone Korma silegone@gmail.com Radhakrishna Kishore Parimi parimirkk@gmail.com Dawit Chernet Kifetew cherudawit@gmail.com <p>In this paper, we introduce the concept of a fuzzy lattice ordered group, which is based on a fuzzy lattice that Chon developed in his paper "Fuzzy Partial Order Relations and Fuzzy Lattice". We will also discuss fuzzy lattice-ordered groups in detail, provide several results that are analogous to the classical theory of lattice-ordered groups, and characterize the relationship between a fuzzy lattice-ordered group using its level set and support. Moreover, we define the concepts of $fl$-subgroups, quotients, and cosets of $fl$-groups and obtain some fundamental results for these fuzzy algebraic structures.</p> 2024-06-30T00:00:00+09:00 Copyright (c) 2024 Korean Journal of Mathematics https://kkms.org/index.php/kjm/article/view/1670 On the adapted partial differential equation for general diploid model of selection at a single locus 2024-02-24T15:59:23+09:00 Won Choi choiwon@inu.ac.kr <p>Assume that at a certain locus there are three genotypes and that for every one progeny produced by an $I^A I^A$ homozygote, the heterozygote $I^A I^B$ produces. W. Choi found the adapted partial differential equations for the density and operator of the frequency for one gene and applied this adapted partial differential equations to several diploid model. Also, he found adapted partial differential equations for the diploid model against recessive homozygotes and in case that the alley frequency occurs after one generation of selection when there is no dominance. <span style="font-size: 0.875rem; font-family: 'Noto Sans', 'Noto Kufi Arabic', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;">(see. [1,2]).</span></p> <div class="page" title="Page 1"> <div class="layoutArea"> <div class="column"> <p>In this paper, we find the adapted partial equations for the model of selection against heterozygotes and in case that the allele frequency changes after one generation of selection when there is overdominance. Finally, we shall find the partial differential equation of general type of selection at diploid model and it also shall apply to actual examples. This is a very meaningful result in that it can be applied in any model.</p> </div> </div> </div> 2024-06-30T00:00:00+09:00 Copyright (c) 2024 Korean Journal of Mathematics https://kkms.org/index.php/kjm/article/view/1736 Generalized $\alpha$-Köthe Toeplitz duals of certain difference sequence spaces 2024-03-16T16:55:11+09:00 Sandeep Gupta sandeep80.gupta@rediffmail.com Ritu ritukharb91@gmail.com Manoj Kumar manojantil18@gmail.com <p>In this paper, we compute the generalized $\alpha$-K\"{o}the Toeplitz duals of the $X$-valued (Banach space) difference sequence spaces $E(X,\Delta)$, $E(X,\Delta_v)$ and obtain a generalization of the existing results for $\alpha$-duals of the classical difference sequence spaces $E(\Delta)$ and $E(\Delta_v)$ of scalars, $E \in \{ \ell_\infty,c,c_0 \}$. Apart from this, we compute the generalized $\alpha$-Köthe Toeplitz duals for $E(X,\Delta^r)\; r\geq0$ integer and observe that the results agree with corresponding results for scalar cases.</p> 2024-06-30T00:00:00+09:00 Copyright (c) 2024 Korean Journal of Mathematics https://kkms.org/index.php/kjm/article/view/1740 On the weakened hypotheses-based generalizations of the Enestr\"{o}m-Kakeya theorem 2024-02-14T17:38:03+09:00 Shahbaz Mir shahbaz_04phd19@nitsri.net Abdul Liman abliman@rediffmail.com <p>According to the well-known Enestr\"{o}m-Kakeya Theorem, all the zeros of a polynomial $P(z)=\sum\limits_{s=0}^{n}a_sz^s$ of degree $n$ with real coefficients satisfying $a_n\geq a_{n-1}\geq\cdots\geq a_1\geq a_0&gt;0$ lie in the complex plane $|z|\leq1.$ We provide comparable results with hypotheses relating to the real and imaginary parts of the coefficients as well as the coefficients' moduli in response to recent findings about an Enestr\"{o}m-Kakeya ``type" condition on real coefficients. Our findings so broadly extend the other previous findings.</p> 2024-06-30T00:00:00+09:00 Copyright (c) 2024 Korean Journal of Mathematics https://kkms.org/index.php/kjm/article/view/1769 Expansive type mappings in dislocated quasi-metric space with some fixed point results and application 2024-04-10T17:48:57+09:00 Haripada Das dasharipada088@gmail.com Nilakshi Goswami nila_g2003@yahoo.co.in <p>In this paper, we prove some new fixed point results for expansive type mappings in complete dislocated quasi-metric space. A common fixed point result is also established considering such mappings. Suitable examples are provided to demonstrate our results. The solution to a system of Fredholm integral equations is also established to show the applicability of our results.</p> 2024-06-30T00:00:00+09:00 Copyright (c) 2024 Korean Journal of Mathematics https://kkms.org/index.php/kjm/article/view/1781 Ruled surfaces generated by Salkowski curve and its Frenet vectors in Euclidean 3-space 2024-03-28T10:13:14+09:00 Ebru Çakıl ebru.cakil95@gmail.com Sümeyye Gür Mazlum sumeyyegur@gumushane.edu.tr <p>In present study, we introduce ruled surfaces whose base curve is the Salkowski curve in Euclidean 3-space and whose generating lines consist of the Frenet vectors of this curve (tangent, principal normal and binormal vectors). Then, we produce regular surfaces from a vector with real coefficients, which is a linear combination of these vectors, and we examine some special cases for these surfaces. Moreover, we present some geometric properties and graphics of all these surfaces.</p> 2024-06-30T00:00:00+09:00 Copyright (c) 2024 Korean Journal of Mathematics https://kkms.org/index.php/kjm/article/view/1614 Faber polynomial coefficient estimates for analytic bi-univalent functions associated with Gregory coefficients 2024-02-02T15:23:04+09:00 Serap Bulut serap.bulut@kocaeli.edu.tr <p>In this work, we consider the function<br />\begin{equation*}<br />\Psi (z)=\frac{z}{\ln \left( 1+z\right) }=1+\sum_{n=1}^{\infty }G_{n}z^{n}<br />\end{equation*}<br />whose coefficients $G_{n}$ are the Gregory coefficients related to Stirling numbers of the first kind and introduce a new subclass $\mathcal{G}_{\Sigma }^{\lambda,\mu}\left( \Psi \right) $ of analytic bi-univalent functions subordinate to the function $\Psi $.</p> <p>For functions belong to this class, we investigate the estimates for the general Taylor-Maclaurin coefficients by using the Faber polynomial expansions. In certain cases, our estimates improve some of those existing coefficient bounds.</p> 2024-06-30T00:00:00+09:00 Copyright (c) 2024 Korean Journal of Mathematics https://kkms.org/index.php/kjm/article/view/1747 A study on Milne-type inequalities for a specific fractional integral operator with applications 2024-02-17T01:47:14+09:00 Arslan Munir munirarslan999@gmail.com Ather Qayyum dratherqayyum@um.edu.my Laxmi Rathour laxmirathour817@gmail.com Gulnaz Atta gulnaz.atta@ue.edu.pk Siti Suzlin Supadi suzlin@um.edu.my Usman Ali ua3260040@gmail.com <p>Fractional integral operators have been studied extensively in the last few decades by various mathematicians, because it plays a vital role in the developments of new inequalities. The main goal of the current study is to establish some new Milne-type inequalities by using the special type of fractional integral operator i.e Caputo Fabrizio operator. Additionally, generalization of these developed Milne-type inequalities for $s$-convex function are also given. Furthermore, applications to some special means, quadrature formula, and $q$-digamma functions are presented.</p> 2024-06-30T00:00:00+09:00 Copyright (c) 2024 Korean Journal of Mathematics https://kkms.org/index.php/kjm/article/view/1748 A $(k,\mu)$-contact metric manifold as an $\eta-$Einstein soliton 2024-04-08T14:43:45+09:00 Arup Kumar Mallick arupkm14@gmail.com Arindam Bhattacharyya bhattachar1968@yahoo.co.in <p> The aim of the paper is to study an $\eta$-Einstein soliton on $(2n+1)$-dimensional $(k,\mu)$-contact metric manifold. At first, we establish various results related to $(2n+1)$-dimensional $(k,\mu)$-contact metric manifold that exhibit an $\eta$-Einstein soliton. Next we study some curvature conditions admitting an $\eta$-Einstein soliton on $(2n+1)$-dimensional $(k,\mu)$-contact metric manifold. Furthermore, we consider specific conditions associated with an $\eta$-Einstein soliton on $(2n+1)$-dimensional $(k,\mu)$-contact metric manifold. Finally, we show the existance of an $\eta$-Einstein soliton on $(k,\mu)$-contact metric manifold.</p> 2024-06-30T00:00:00+09:00 Copyright (c) 2024 Korean Journal of Mathematics https://kkms.org/index.php/kjm/article/view/1636 Some fixed point results on double controlled cone metric spaces 2024-05-15T02:50:50+09:00 A. Herminau Jothy herminaujothy.a@bdu.ac.in P. S. Srinivasan pssrini@bdu.ac.in Laxmi Rathour laxmirathour817@gmail.com R. Theivaraman deivaraman@gmail.com S. Thenmozhi sthenu85@gmail.com <p>In this text, we investigate some fixed point results in double-controlled cone metric spaces using several contraction mappings such as the B-contraction, the Hardy-Rogers contraction, and so on. Additionally, we prove the same fixed point results by using rational type contraction mappings, which were discussed by the authors Dass. B. K and Gupta. S. Also, a few examples are included to illustrate the results. Finally, we discuss some applications that support our main results in the field of applied mathematics.</p> 2024-06-30T00:00:00+09:00 Copyright (c) 2024 Korean Journal of Mathematics https://kkms.org/index.php/kjm/article/view/1758 Note on Newton-type inequalities involving tempered fractional integrals 2024-04-13T19:50:40+09:00 Fatih Hezenci fatihezenci@gmail.com Huseyin Budak hsyn.budak@gmail.com <pre>We propose a new method of investigation of an integral equality associated with tempered fractional integrals. In addition to this, several Newton-type inequalities are considered for differentiable convex functions by taking the modulus of the newly established identity. Moreover, we establish some Newton-type inequalities with the help of H\"{o}lder and power-mean inequality. Furthermore, several new results are presented by using special choices of obtained inequalities.</pre> 2024-06-30T00:00:00+09:00 Copyright (c) 2024 Korean Journal of Mathematics