권호 표지

Journal of the Korean Mathematical Society (대한수학회지)

Korean Mathematical Society

  • Bimonthly
  • /
  • 0304-9914(pISSN)
  • /
  • 2234-3008(eISSN)

Aim & Scope

This journal endeavors to publish significant research of broad interests in pure and applied mathematics. One volume is published each year, and each volume consists of six issues (January, March, May, July, September, November).

http://jkms.kms.or.kr/submission KSCI KCI SCOPUS SCI SCIE

Volume 49 Issue 3

  1. Campion, Maria Jesus;Candeal, Juan Carlos;Indurain, Esteban;Mehta, Ghanshyam Bhagvandas 449
    https://doi.org/10.4134/JKMS.2012.49.3.449 PDF KSCI
    In the present paper, we study the relationship between continuous order-representability and the fulfillment of the usual covering properties on topological spaces. We also consider the case of some algebraic structures providing an application of our results to the social choice theory context.
  2. Zitnik, Arjana;Horvat, Boris;Pisanski, Tomaz 475
    https://doi.org/10.4134/JKMS.2012.49.3.475 PDF KSCI
    In 1950 a class of generalized Petersen graphs was introduced by Coxeter and around 1970 popularized by Frucht, Graver and Watkins. The family of $I$-graphs mentioned in 1988 by Bouwer et al. represents a slight further albeit important generalization of the renowned Petersen graph. We show that each $I$-graph $I(n,j,k)$ admits a unit-distance representation in the Euclidean plane. This implies that each generalized Petersen graph admits a unit-distance representation in the Euclidean plane. In particular, we show that every $I$-graph $I(n,j,k)$ has an isomorphic $I$-graph that admits a unit-distance representation in the Euclidean plane with a $n$-fold rotational symmetry, with the exception of the families $I(n,j,j)$ and $I(12m,m,5m)$, $m{\geq}1$. We also provide unit-distance representations for these graphs.
  3. Yom, Peter Dong-Jun 493
    https://doi.org/10.4134/JKMS.2012.49.3.493 PDF KSCI
    In this article, we give a characterization theorem for a class of corank-1 Butler groups of the form $\mathcal{G}$($A_1$, ${\ldots}$, $A_n$). In particular, two groups $G$ and $H$ are quasi-isomorphic if and only if there is a label-preserving bijection ${\phi}$ from the edges of $T$ to the edges of $U$ such that $S$ is a circuit in T if and only if ${\phi}(S)$ is a circuit in $U$, where $T$, $U$ are quasi-representing graphs for $G$, $H$ respectively.
  4. Asgari, Shadi;Haghany, Ahmad 503
    https://doi.org/10.4134/JKMS.2012.49.3.503 PDF KSCI
    The concepts of t-extending and t-Baer for modules are generalized to those of FI-t-extending and FI-t-Baer respectively. These are also generalizations of FI-extending and nonsingular quasi-Baer properties respectively and they are inherited by direct summands. We shall establish a close connection between the properties of FI-t-extending and FI-t-Baer, and give a characterization of FI-t-extending modules relative to an annihilator condition.
  5. Meng, Xuejing;Yin, Baojian 515
    https://doi.org/10.4134/JKMS.2012.49.3.515 PDF KSCI
    This work focuses on the general decay stability of nonlinear stochastic differential equations with unbounded delay. A Razumikhin-type theorem is first established to obtain the moment stability but without almost sure stability. Then an improved edition is presented to derive not only the moment stability but also the almost sure stability, while existing Razumikhin-type theorems aim at only the moment stability. By virtue of the $M$-matrix techniques, we further develop the aforementioned Razumikhin-type theorems to be easily implementable. Two examples are given for illustration.
  6. Corcino, Roberto B.;Montero, Charles B. 537
    https://doi.org/10.4134/JKMS.2012.49.3.537 PDF KSCI
    In this paper, we define a $p$, $q$-difference operator and obtain an explicit formula which is used to express the $p$, $q$-analogue of the unified generalization of Stirling numbers and its exponential generating function in terms of the $p$, $q$-difference operator. Explicit formulas for the non-central $q$-Stirling numbers of the second kind and non-central $q$-Lah numbers are derived using the new $q$-analogue of Newton's interpolation formula. Moreover, a $p$, $q$-analogue of Newton's interpolation formula is established.
  7. Chen, Yanping;Huang, Yunqing;Hou, Tianliang 549
    https://doi.org/10.4134/JKMS.2012.49.3.549 PDF KSCI
    In this paper asymptotic error expansions for mixed finite element approximations to a class of second order elliptic optimal control problems are derived under rectangular meshes, and the Richardson extrapolation of two different schemes and interpolation defect correction can be applied to increase the accuracy of the approximations. As a by-product, we illustrate that all the approximations of higher accuracy can be used to form a class of a posteriori error estimators of the mixed finite element method for optimal control problems.
  8. Ahmadi, Ahmad;Askari-Hemmat, Ataollah 571
    https://doi.org/10.4134/JKMS.2012.49.3.571 PDF KSCI
    Let $G$ be a metrizable, ${\sigma}$-compact locally compact abelian group with a compact open subgroup. In this paper we define the Gramian and the dual Gramian operators for shift invariant subspaces of $L^2(G)$ and we use them to characterize shift generated dual frames for shift in- variant spaces, which forms a frame for a subspace of $L^2(G)$. We present necessary and sufficient conditions for which standard dual is a unique SG-dual frame of type I and type II.
  9. Lee, Ki-Ahm;Rhee, Eun-Jai 585
    https://doi.org/10.4134/JKMS.2012.49.3.585 PDF KSCI
    In this paper we consider the evolution of the rolling stone with a rotationally symmetric nonconvex compact initial surface ${\Sigma}_0$ under the Gauss curvature flow. Let $X:S^n{\times}[0,\;{\infty}){\rightarrow}\mathbb{R}^{n+1}$ be the embeddings of the sphere in $\mathbb{R}^{n+1}$ such that $\Sigma(t)=X(S^n,t)$ is the surface at time t and ${\Sigma}(0)={\Sigma}_0$. As a consequence the parabolic equation describing the motion of the hypersurface becomes degenerate on the interface separating the nonconvex part from the strictly convex side, since one of the curvature will be zero on the interface. By expressing the strictly convex part of the surface near the interface as a graph of a function $z=f(r,t)$ and the non-convex part of the surface near the interface as a graph of a function $z={\varphi}(r)$, we show that if at time $t=0$, $g=\frac{1}{n}f^{n-1}_{r}$ vanishes linearly at the interface, the $g(r,t)$ will become smooth up to the interface for long time before focusing.
  10. Aydogdu, Pinar;Lee, Yang;Ozcan, A. Cigdem 605
    https://doi.org/10.4134/JKMS.2012.49.3.605 PDF KSCI
    A ring $R$ is called semiregular if $R/J$ is regular and idem-potents lift modulo $J$, where $J$ denotes the Jacobson radical of $R$. We give some characterizations of rings $R$ such that idempotents lift modulo $J$, and $R/J$ satisfies one of the following conditions: (one-sided) unit-regular, strongly regular, (unit, strongly, weakly) ${\pi}$-regular.
  11. Choi, Hyun-Suk;Kye, Seung-Hyeok 623
    https://doi.org/10.4134/JKMS.2012.49.3.623 PDF KSCI
    The convex cone $\mathbb{V}_1$ generated by separable states is contained in the cone $\mathbb{T}$ of all positive semi-definite block matrices whose block transposes are also positive semi-definite. We characterize faces of the cone $\mathbb{V}_1$ induced by faces of the cone $\mathbb{T}$ which are determined by pairs of subspaces of matrices.
  12. Mohamed, Bouhamida;Bachir, Daaou;Abdellah, Mansouri;Mohammed, Chenafa 641
    https://doi.org/10.4134/JKMS.2012.49.3.641 PDF KSCI
    The goal of this paper is to develop a nonlinear observer-based control strategy for a multi-variables continuous stirred tank reactor (CSTR). A new robust nonlinear observer is constructed to estimate the whole process state variables. The observer is coupled with a nonlinear controller, designed based on the input-output linearization for controlling the concentration and reactor temperature. The closed loop system is shown to be globally asymptotically stable based on Lyapunov arguments. Finally, computer simulations are developed for showing the performance of the proposed controller.
  13. Osekowski, Adam 659
    https://doi.org/10.4134/JKMS.2012.49.3.659 PDF KSCI
    For any $K$ > $2/{\pi}$ we determine the optimal constant $L(K)$ for which the following holds. If $u$, $tilde{u}$ are conjugate harmonic functions on the unit disc with $\tilde{u}(0)=0$, then $$ {\int}_{-\pi}^{\pi}{\mid}\tilde{u}(e^{i\phi}){\mid}\frac{d{\phi}}{2{\pi}}{\leq}K{\int}_{-\pi}^{\pi}{\mid}u(e^{i{\phi}}){\mid}{\log}^+{\mid}u(e^{i{\phi}}){\mid}\frac{d{\phi}}{2{\pi}}+L(K).$$ We also establish a related estimate for orthogonal harmonic functions given on Euclidean domains as well as an extension concerning orthogonal martingales under differential subordination.