권호 표지

Bulletin of the Korean Mathematical Society (대한수학회보)

Korean Mathematical Society

  • Bimonthly
  • /
  • 1015-8634(pISSN)
  • /
  • 2234-3016(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://bkms.kms.or.kr/submission KSCI KCI SCOPUS SCI SCIE

Volume 45 Issue 4

  1. Song, Yisheng 607
    https://doi.org/10.4134/BKMS.2008.45.4.607 PDF KSCI
    We present coincidence points and common fixed point results for (f, g)-contractive mapping and (f, g)-nonexpansive mappings. Our results generalize and complement various known results existing in the literature.
  2. Yavuz, Emel;Polatoglu, Yasar;Owa, Shigeyoshi 615
    https://doi.org/10.4134/BKMS.2008.45.4.615 PDF KSCI
    For analytic functions f(z) in the open unit disc $\mathbb{D}$, an operator $N_{\alpha}(f(z))$ relating with starlike functions is introduced. The object of the present paper is to discuss some properties of the operator $N_{\alpha}(f(z))$.
  3. De Filippis, Vincenzo 621
    https://doi.org/10.4134/BKMS.2008.45.4.621 PDF KSCI
    Let R be a prime ring of characteristic different from 2, C the extended centroid of R, and $\delta$ a generalized derivations of R. If [[$\delta(x)$, x], $\delta(x)$] = 0 for all $x\;{\in}\;R$ then either R is commutative or $\delta(x)\;=\;ax$ for all $x\;{\in}\;R$ and some $a\;{\in}\;C$. We also obtain some related result in case R is a Banach algebra and $\delta$ is either continuous or spectrally bounded.
  4. Yu, Yanhua;Liu, Huili 631
    https://doi.org/10.4134/BKMS.2008.45.4.631 PDF KSCI
    In this paper, the parabola will be characterized as the plane curve whose curvature function and support function satisfy a condition, where we define the support function as the distance from origin to the tangent line.
  5. Xue, Zhiqun 635
    https://doi.org/10.4134/BKMS.2008.45.4.635 PDF KSCI
    In this paper, we prove that the equivalence between the convergence of Mann and Ishikawa iterations for the generalized Lipschitzian and $\Phi$-strongly pseudocontractive mappings in real uniformly smooth Banach spaces. Our results significantly generalize the recent known results of [B. E. Rhoades and S. M. Soltuz, The equivalence of Mann iteration and Ishikawa iteration for non-Lipschitz operators, Int. J. Math. Math. Sci. 42 (2003), 2645.2651].
  6. Honary, Bahman;Bahabadi, Alireza Zamani 645
    https://doi.org/10.4134/BKMS.2008.45.4.645 PDF KSCI
    Let M be a generalized homogeneous compact space, and let Z(M) denotes the space of homeomorphisms of M with the $C^0$ topology. In this paper, we show that if the interior of the set of weak stable homeomorphisms on M is not empty then for any open subset W of Z(M) containing only weak stable homeomorphisms the orbital shadowing property is generic in W.
  7. Kim, Hee-Sik;Neggers, Joseph 651
    https://doi.org/10.4134/BKMS.2008.45.4.651 PDF KSCI
    Given binary operations "*" and "$\circ$" on a set X, define a product binary operation "$\Box$" as follows: $x{\Box}y\;:=\;(x\;{\ast}\;y)\;{\circ}\;(y\;{\ast}\;x)$. This in turn yields a binary operation on Bin(X), the set of groupoids defined on X turning it into a semigroup (Bin(X), $\Box$)with identity (x * y = x) the left zero semigroup and an analog of negative one in the right zero semigroup (x * y = y). The composition $\Box$ is a generalization of the composition of functions, modelled here as leftoids (x * y = f(x)), permitting one to study the dynamics of binary systems as well as a variety of other perspectives also of interest.
  8. Vanani, Solat Karimi;Aminataei, Azim 663
    https://doi.org/10.4134/BKMS.2008.45.4.663 PDF KSCI
    In this paper, the aim is to solve the neutral delay differential equations in the following form using multiquadric approximation scheme, (1) $$\{_{\;y(t)\;=\;{\phi}(t),\;\;\;\;\;t\;{\leq}\;{t_1},}^{\;y'(t)\;=\;f(t,\;y(t),\;y(t\;-\;{\tau}(t,\;y(t))),\;y'(t\;-\;{\sigma}(t,\;y(t)))),\;{t_1}\;{\leq}\;t\;{\leq}\;{t_f},}$$ where f : $[t_1,\;t_f]\;{\times}\;R\;{\times}\;R\;{\times}\;R\;{\rightarrow}\;R$ is a smooth function, $\tau(t,\;y(t))$ and $\sigma(t,\;y(t))$ are continuous functions on $[t_1,\;t_f]{\times}R$ such that t-$\tau(t,\;y(t))$ < $t_f$ and t - $\sigma(t,\;y(t))$ < $t_f$. Also $\phi(t)$ represents the initial function or the initial data. Hence, we present the advantage of using the multiquadric approximation scheme. In the sequel, presented numerical solutions of some experiments, illustrate the high accuracy and the efficiency of the proposed method even where the data points are scattered.
  9. Hussain, Nawab;Abbas, Mujahid;Kim, Jong-Kyu 671
    https://doi.org/10.4134/BKMS.2008.45.4.671 PDF KSCI
    Necessary conditions for the existence of common fixed points for noncommuting mappings satisfying generalized contractive conditions in a Menger convex metric space are obtained. As an application, related results on best approximation are derived. Our results generalize various well known results.
  10. Khan, Liaqat Ali 681
    https://doi.org/10.4134/BKMS.2008.45.4.681 PDF KSCI
    We give a characterization of trans-separability for the function spaces ($C_b(X,\;E)$, $\beta$), (C(X, E), k) and ($C_b(X,\;E)$, u) in the case of E any general topological vector space.
  11. Jun, Jae-Bok;Yildiz, Ahmet;De, Uday Chand 689
    https://doi.org/10.4134/BKMS.2008.45.4.689 PDF KSCI
    In this paper we prove that a $\phi$-recurrent (k, $\mu$)-contact metric manifold is an $\eta$-Einstein manifold with constant coefficients. Next, we prove that a three-dimensional locally $\phi$-recurrent (k, $\mu$)-contact metric manifold is the space of constant curvature. The existence of $\phi$-recurrent (k, $\mu$)-manifold is proved by a non-trivial example.
  12. Ceven, Yilmaz;Ozturk, Mehmet Ali 701
    https://doi.org/10.4134/BKMS.2008.45.4.701 PDF KSCI
    In this paper, as a generalization of derivation on a lattice, the notion of f-derivation for a lattice is introduced and some related properties are investigated.
  13. Choi, So-Young;Koo, Ja-Kyung 709
    https://doi.org/10.4134/BKMS.2008.45.4.709 PDF KSCI
    We construct certain ring class fields over an imaginary quadratic field by making use of Shimura's canonical models and extend the result of Chen-Yui ([1] Theorem 3.7.5(2)) to the case where (a, b, N) $\neq$ N or (a/N, N) $\neq$ 1 for a positive integer N > 1.
  14. Plubtieng, Somyot;Wangkeeree, Rattanaporn 717
    https://doi.org/10.4134/BKMS.2008.45.4.717 PDF KSCI
    Let H be a real Hilbert space and S = {T(s) : $0\;{\leq}\;s\;<\;{\infty}$} be a nonexpansive semigroup on H such that $F(S)\;{\neq}\;{\emptyset}$ For a contraction f with coefficient 0 < $\alpha$ < 1, a strongly positive bounded linear operator A with coefficient $\bar{\gamma}$ > 0. Let 0 < $\gamma$ < $\frac{\bar{\gamma}}{\alpha}$. It is proved that the sequences {$x_t$} and {$x_n$} generated by the iterative method $$x_t\;=\;t{\gamma}f(x_t)\;+\;(I\;-\;tA){\frac{1}{{\lambda}_t}}\;{\int_0}^{{\lambda}_t}\;T(s){x_t}ds,$$ and $$x_{n+1}\;=\;{\alpha}_n{\gamma}f(x_n)\;+\;(I\;-\;{\alpha}_nA)\frac{1}{t_n}\;{\int_0}^{t_n}\;T(s){x_n}ds,$$ where {t}, {${\alpha}_n$} $\subset$ (0, 1) and {${\lambda}_t$}, {$t_n$} are positive real divergent sequences, converges strongly to a common fixed point $\tilde{x}\;{\in}\;F(S)$ which solves the variational inequality $\langle({\gamma}f\;-\;A)\tilde{x},\;x\;-\;\tilde{x}{\rangle}\;{\leq}\;0$ for $x\;{\in}\;F(S)$.
  15. Cieplinski, Krzysztof 729
    https://doi.org/10.4134/BKMS.2008.45.4.729 PDF KSCI
    In this paper we characterize multi-Jensen functions f : $V^n\;{\rightarrow}\;W$, where n is a positive integer, V, W are commutative groups and V is uniquely divisible by 2. Moreover, under the assumption that f : $\mathbb{R}\;{\rightarrow}\;\mathbb{R}$ is Borel measurable, we obtain representation of f (respectively, f, g, h : $\mathbb{R}\;{\rightarrow}\;\mathbb{R}$) such that the Jensen difference $$2f\;\(\frac{x\;+\;y}{2}\)\;-\;f(x)\;-\;f(y)$$ (respectively, the Pexider difference $$2f\;\(\frac{x\;+\;y}{2}\)\;-\;g(x)\;-\;h(y))$$ takes values in a countable subgroup of $\mathbb{R}$.
  16. Koh, Hee-Jeong;Kang, Dong-Seung 739
    https://doi.org/10.4134/BKMS.2008.45.4.739 PDF KSCI
    In this paper, we obtain the general solution of a generalized cubic functional equation, the Hyers-Ulam-Rassias stability, and the stability by using the alternative fixed point for a generalized cubic functional equation $$4f(\sum_{j=1}^{n-1}\;x_j\;+\;mx_n)\;+\;4f(\sum_{j=1}^{n-1}\;x_j+mx_n\;x_j\;-\;mx_n}\;+\;m^2\sum_{j=1}^{n-1}\;(f(2x_j)\;=\;8f(\sum_{j=1}^{n-1}\;x_j)\;+\;4m^2{\sum_{j=1}^{n-1}}\;\(f(x_j+x_n)\;+\;f(x_j-x_n)\)$$ for a positive integer $m\;{\geq}\;1$.
  17. Al-Hawary, Talal 749
    https://doi.org/10.4134/BKMS.2008.45.4.749 PDF KSCI
    In this paper, we introduce the relatively new notion of fuzzy ${\omega}^O$-open set. We prove that the collection of all fuzzy ${\omega}^O$-open subsets of a fuzzy topological space forms a fuzzy topology that is finer than the original one. Several characterizations and properties of this class are also given as well as connections to other well-known "fuzzy generalized open" subsets.
  18. Zulfiqar, Muhammad 757
    https://doi.org/10.4134/BKMS.2008.45.4.757 PDF KSCI
    In this paper, we generalize a few results of [7, 10] for lower radical classes of rings, by using the limit ordinal construction for lower radical classes of hemirings.
  19. Kikianty, Eder;Dragomir, Sever S.;Cerone, Pietro 763
    https://doi.org/10.4134/BKMS.2008.45.4.763 PDF KSCI
    An Ostrowski type inequality is developed for estimating the deviation of the integral mean of an absolutely continuous function, and the linear combination of its values at k + 1 partition points, on a segment of (real) linear spaces. Several particular cases are provided which recapture some earlier results, along with the results for trapezoidal type inequalities and the classical Ostrowski inequality. Some inequalities are obtained by applying these results for semi-inner products; and some of these inequalities are proven to be sharp.
  20. Yoon, Dae-Ki;Kim, Hong-Joong;Hwang, Woon-Jae 781
    https://doi.org/10.4134/BKMS.2008.45.4.781 PDF KSCI
    In this paper, we describe the application procedure of the adaptive mesh refinement (AMR) for the weighted essentially non-oscillatory schemes (WENO), and observe the effects of the derived algorithm when problems have piecewise smooth solutions containing discontinuities. We find numerically that the dissipation of the WENO scheme can be lessened by the implementation of AMR while the accuracy is maintained. We deduce from the experiments that the AMR-implemented WENO scheme captures shocks more efficiently than the WENO method using uniform grids.
  21. Huh, Chan;Kim, Nam-Kyun;Lee, Yang 797
    https://doi.org/10.4134/BKMS.2008.45.4.797 PDF KSCI
    Let R be a ring and I be a proper ideal of R. For the case of R being commutative, Anderson proved that (*) there are only finitely many prime ideals minimal over I whenever every prime ideal minimal over I is finitely generated. We in this note extend the class of rings that satisfies the condition (*) to noncommutative rings, so called homomorphically IFP, which is a generalization of commutative rings. As a corollary we obtain that there are only finitely many minimal prime ideals in the polynomial ring over R when every minimal prime ideal of a homomorphically IFP ring R is finitely generated.