https://kkms.org/index.php/kjm/issue/feed Korean Journal of Mathematics 2025-03-30T16:12:43+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/1941 On the relations for limiting case of selection with equilibrium and mutation of diploid model 2024-09-05T12:52:34+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. Choi 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. Also he 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 ([1], [2]). <br /><br />In this paper, we start with the limiting case of selection against recessive alleles. For the time being, assume that the trajectories of $p_t$ and $q_t$ at time $t$ can be approximated by paths which are continuous and therefore we have a diffusion process. We shall find the relations for time $t$, $p_t$ and $q_t$ and apply to equilibrium state and mutation.</p> 2025-03-30T00:00:00+09:00 Copyright (c) 2025 Korean Journal of Mathematics https://kkms.org/index.php/kjm/article/view/2015 Generalized hilbert operator on bergman spaces 2024-12-15T17:18:51+09:00 Simi Bhuyan simi@gauhati.ac.in Sunanda Naik snaik@gauhati.ac.in <p>We consider the generalized Hilbert operator $\mathcal{H_\beta}$ for $\beta\geq 0$ and find the condition on the parameter $\beta$ for which the operator $\mathcal{H_\beta}$ is bounded on the Bergman space $ A^p$ for $2&lt;p&lt;\infty$. Also, we estimates the upper bound of the norm on $A^p$. Further shows that $\mathcal{H_\beta}$ is not bounded on $ A^2$ for $0\leq\beta&lt;1.$</p> 2025-03-30T00:00:00+09:00 Copyright (c) 2025 Korean Journal of Mathematics https://kkms.org/index.php/kjm/article/view/2007 A characterization of $S_1$-projective modules 2024-11-30T18:59:04+09:00 Hwankoo Kim hkkim@hoseo.edu Najib Mahdou mahdou@hotmail.com El Houssaine Oubouhou hossineoubouhou@gmail.com <p>Recently, Zhao, Pu, Chen, and Xiao introduced and investigated novel concepts regarding $S$-torsion exact sequences, $S$-torsion commutative diagrams, and $S_i$-projective modules (for $i = 1, 2$) in the context of a commutative ring $R$ and a multiplicative subset $S$ of $R$. Their research included various results, such as proving that an $R$-module is $S_1$-projective if it is $S$-torsion isomorphic to a projective module. In this paper, we further examine properties of $S$-torsion exact sequences and $S$-torsion commutative diagrams, and we establish the equivalence between an $R$-module being $S_1$-projective and its $S$-torsion isomorphism to a projective module.</p> 2025-03-30T00:00:00+09:00 Copyright (c) 2025 Korean Journal of Mathematics https://kkms.org/index.php/kjm/article/view/1999 On some ideals defined by an arithmetic sequence 2024-11-30T18:01:25+09:00 Jonghyeon Gil leakry@korea.ac.kr <p>This paper investigates properties of ideals in the affine and homogeneous projective coordinate rings of the plane, defined using arithmetic sequence<br />\begin{equation*}<br />\{a_\ell = a+\ell d ~|~ \ell \ge 0 \}<br />\end{equation*} <br />for some positive integers $a$ and $d$. Specifically, we study two types of ideals:<br />$I(a,d)$ is generated by $D(a,d)$ in $K[x,y]$ and $J(a,d)$ is generated by $E(a,d)$ in $K[x,y,z]$ where <br />\begin{equation*}<br />D(a,d) =\{f_\ell = x^{a_{\ell}}-y^{a_{\ell+1}} ~|~ \ell\ge 0\}<br />\end{equation*}<br />and<br />\begin{equation*}<br />E(a,d) =\{F_\ell = x^{a_{\ell}} z^d -y^{a_{\ell+1}} ~|~ \ell\ge 0\}.<br />\end{equation*}<br />This paper provides detailed answers to several problems, including finding finite generating sets, describing the zero locus of these ideals, and determining their Hilbert functions. Finally, the Castelnuovo-Mumford regularity and the minimal free resolution of the homogeneous coordinate ring and multi secant line are discussed.</p> 2025-03-30T00:00:00+09:00 Copyright (c) 2025 Korean Journal of Mathematics https://kkms.org/index.php/kjm/article/view/1731 The $n$-generalized composition operators from Zygmund spaces to $Q_K(p,q)$ spaces 2024-07-22T13:54:27+09:00 taha ibrahim yassen taha_hmour@yahoo.com <p>The boundedness and compactness of the so-called $n$-generalized composition operator $c^{\mathfrak{g},n}_\varphi$ from the class of Zygmund-type spaces into $Q_K(p,q)$ spaces are characterized in this paper.</p> 2025-03-30T00:00:00+09:00 Copyright (c) 2025 Korean Journal of Mathematics https://kkms.org/index.php/kjm/article/view/1629 Hermite-Hadamard type inequalities for preinvex functions with applications 2023-09-26T09:46:49+09:00 Shiwani Singh shiwanisingh1312@bhu.ac.in Shashi Kant Mishra shashikant.mishra@bhu.ac.in Vandana Singh svandana96@bhu.ac.in Pankaj Pankaj pankaj22iitr@bhu.ac.in Hüseyin BUDAK hsyn.budak@gmail.com <p><br>In this article, we establish new Hermite-Hadamard Type inequalities for functions whose first derivative in absolute value are preinvex. Further, we give some application of our obtained results to some special means of real numbers. Moreover, we discuss several special cases of the results obtained in this paper.</p> 2025-03-30T00:00:00+09:00 Copyright (c) 2025 Korean Journal of Mathematics https://kkms.org/index.php/kjm/article/view/1615 Rough $\mathcal{I}$-convergence of sequences in probabilistic normed spaces 2023-09-03T17:41:11+09:00 Amar Kumar Banerjee akbanerjee1971@gmail.com Nesar Hossain nesarhossain24@gmail.com <p>In this paper, we have studied the idea of rough $\mathcal{I}$-convergence in probabilistic normed spaces which is indeed a generalized version as compared to the notion of rough $\mathcal{I}$-convergence in normed linear spaces. On the other way, it is also a generalization of rough statistical convergence in probabilistic normed spaces. Furthermore, we have defined the notion of rough $\mathcal{I}$-cluster points and have proved some important results associated with the set of rough $\mathcal{I}$-limits of a sequence in the same space.</p> 2025-03-30T00:00:00+09:00 Copyright (c) 2025 Korean Journal of Mathematics