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 50 Issue 2

  1. Xu, Changjin;Tang, Xianhua;Liao, Maoxin 353
    https://doi.org/10.4134/BKMS.2013.50.2.353 PDF KSCI
    In this paper, a class of delayed predator-prey models of prey migration and predator switching is considered. By analyzing the associated characteristic transcendental equation, its linear stability is investigated and Hopf bifurcation is demonstrated. Some explicit formulae for determining the stability and the direction of the Hopf bifurcation periodic solutions bifurcating from Hopf bifurcations are obtained by using the normal form theory and center manifold theory. Some numerical simulations for justifying the theoretical analysis are also provided. Finally, biological explanations and main conclusions are given.
  2. Plubtieng, Somyot;Sombut, Kamonrat 375
    https://doi.org/10.4134/BKMS.2013.50.2.375 PDF KSCI
    In this paper, we introduce an iterative sequence for finding solution of a system of mixed equilibrium problems and the set of fixed points of a nonexpansive mapping in Hilbert spaces. Then, the weak and strong convergence theorems are proved under some parameters controlling conditions. Moreover, we apply our result to fixed point problems, system of equilibrium problems, general system of variational inequalities, mixed equilibrium problem, equilibrium problem and variational inequality.
  3. Hosseini, Esmaeil 389
    https://doi.org/10.4134/BKMS.2013.50.2.389 PDF KSCI
    Let R be a ring and $\mathcal{Q}$ be a quiver. In this paper we give another definition of purity in the category of quiver representations. Under such definition we prove that the class of all pure injective representations of $\mathcal{Q}$ by R-modules is preenveloping. In case $\mathcal{Q}$ is a left rooted semi-co-barren quiver and R is left Noetherian, we show that every cotorsion flat representation of $\mathcal{Q}$ is pure injective. If, furthermore, R is $n$-perfect and $\mathcal{F}$ is a flat representation $\mathcal{Q}$, then the pure injective dimension of $\mathcal{F}$ is at most $n$.
  4. Bender, Andreas O.;Im, Bo-Hae;Lee, Yoonjin 399
    https://doi.org/10.4134/BKMS.2013.50.2.399 PDF KSCI
    We explicitly construct a thin basis for the set $\mathbf{M}$ of monic polynomials in one variable $t$ over a finite field ${\mathbb{F}}_q$.
  5. Kim, Dohyeong 407
    https://doi.org/10.4134/BKMS.2013.50.2.407 PDF KSCI
    Let E be an elliptic curve over $\mathbb{Q}$ and $p$ be a prime of good supersingular reduction for E. Although the Iwasawa theory of E over the cyclotomic ${\mathbb{Z}}_p$-extension of $\mathbb{Q}$ is well known to be fundamentally different from the case of good ordinary reduction at p, we are able to combine the method of our earlier paper with the theory of Kobayashi [5] and Pollack [8], to give an explicit upper bound for the number of copies of ${\mathbb{Q}}_p/{\mathbb{Z}}_p$ occurring in the $p$-primary part of the Tate-Shafarevich group of E over $\mathbb{Q}$.
  6. Zhang, Zhihua;Shu, Lan;Zheng, Jun;Yang, Yuling 417
    https://doi.org/10.4134/BKMS.2013.50.2.417 PDF KSCI
    Let X be a Banach space and ${\psi}$ a continuous convex function on ${\Delta}_{K+1}$ satisfying certain conditions. Let $(X{\bigoplus}X{\bigoplus}{\cdots}{\bigoplus}X)_{\psi}$ be the ${\psi}$-direct sum of X. In this paper, we characterize the K strict convexity, K uniform convexity and uniform non-$l^N_1$-ness of Banach spaces using ${\psi}$-direct sums.
  7. Kim, Eui Chul 431
    https://doi.org/10.4134/BKMS.2013.50.2.431 PDF KSCI
    Let ($M^3$, $g$) be a 3-dimensional closed Sasakian spin manifold. Let $S_{min}$ denote the minimum of the scalar curvature of ($M^3$, $g$). Let ${\lambda}^+_1$ > 0 be the first positive eigenvalue of the Dirac operator of ($M^3$, $g$). We proved in [13] that if ${\lambda}^+_1$ belongs to the interval ${\lambda}^+_1{\in}({\frac{1}{2}},\;{\frac{5}{2}})$, then ${\lambda}^+_1$ satisfies ${\lambda}^+_1{\geq}{\frac{S_{min}+6}{8}}$. In this paper, we remove the restriction "if ${\lambda}^+_1$ belongs to the interval ${\lambda}^+_1{\in}({\frac{1}{2}},\;{\frac{5}{2}})$" and prove $${\lambda}^+_1{\geq}\;\{\frac{S_{min}+6}{8}\;for\;-\frac{3}{2}<S_{min}{\leq}30, \\{\frac{1+\sqrt{2S_{min}}+4}{2}}\;for\;S_{min}{\geq}30$$.
  8. Kim, Do-Hyung;Kim, Byung Hak 441
    https://doi.org/10.4134/BKMS.2013.50.2.441 PDF KSCI
    It is shown that any two-dimensional globally hyperbolic spacetime with noncompact Cauchy surfaces has no null cut points.
  9. Ayik, Gonca;Caliskan, Basri 445
    https://doi.org/10.4134/BKMS.2013.50.2.445 PDF KSCI
    We consider a congruence ${\rho}$ on a group G as a subsemigroup of the direct product $G{\times}G$. It is well known that a relation ${\rho}$ on G is a congruence if and only if there exists a normal subgroup N of G such that ${\rho}=\{(s,\;t):st^{-1}{\in}N\}$. In this paper we prove that if G is a finitely presented group, and if N is a normal subgroup of G with finite index, then the congruence ${\rho}=\{(s,\;t):st^{-1}{\in}N\}$ on G is finitely presented.
  10. Jingzhe, Wang 451
    https://doi.org/10.4134/BKMS.2013.50.2.451 PDF KSCI
    The main purpose of this paper is using the analytic methods and the properties of Gauss sums to study the computational problem of one kind mean value of the generalized Kloosterman sums and Dirichlet character of polynomials, and give an interesting asymptotic formula for it.
  11. Yan, Hangyu 459
    https://doi.org/10.4134/BKMS.2013.50.2.459 PDF KSCI
    In this paper, Matlis injective modules are introduced and studied. It is shown that every R-module has a (special) Matlis injective preenvelope over any ring R and every right R-module has a Matlis injective envelope when R is a right Noetherian ring. Moreover, it is shown that every right R-module has an ${\mathcal{F}}^{{\perp}1}$-envelope when R is a right Noetherian ring and $\mathcal{F}$ is a class of injective right R-modules.
  12. Mojdeh, Doost Ali;Moghaddam, Seyed Mehdi Hosseini 469
    https://doi.org/10.4134/BKMS.2013.50.2.469 PDF KSCI
    Let G = (V, E) be a graph and k be a positive integer. A $k$-dominating set of G is a subset $S{\subseteq}V$ such that each vertex in $V{\backslash}S$ has at least $k$ neighbors in S. A Roman $k$-dominating function on G is a function $f$ : V ${\rightarrow}$ {0, 1, 2} such that every vertex ${\upsilon}$ with $f({\upsilon})$ = 0 is adjacent to at least $k$ vertices ${\upsilon}_1$, ${\upsilon}_2$, ${\ldots}$, ${\upsilon}_k$ with $f({\upsilon}_i)$ = 2 for $i$ = 1, 2, ${\ldots}$, $k$. In the paper titled "Roman $k$-domination in graphs" (J. Korean Math. Soc. 46 (2009), no. 6, 1309-1318) K. Kammerling and L. Volkmann showed that for any graph G with $n$ vertices, ${{\gamma}_{kR}}(G)+{{\gamma}_{kR}(\bar{G})}{\geq}$ min $\{2n,4k+1\}$, and the equality holds if and only if $n{\leq}2k$ or $k{\geq}2$ and $n=2k+1$ or $k=1$ and G or $\bar{G}$ has a vertex of degree $n$ - 1 and its complement has a vertex of degree $n$ - 2. In this paper we find a counterexample of Kammerling and Volkmann's result and then give a correction to the result.
  13. Kim, Hwankoo;Wang, Fanggui 475
    https://doi.org/10.4134/BKMS.2013.50.2.475 PDF KSCI
    We give some characterizations of injective modules over ${\omega}$-Noetherian rings. It is also shown that each localization of a GV-torsion-free injective module over a ${\omega}$-Noetherian ring is injective.
  14. Yang, Zhen-Hang 485
    https://doi.org/10.4134/BKMS.2013.50.2.485 PDF KSCI
    In this paper, the Schur convexity is generalized to Schur $f$-convexity, which contains the Schur geometrical convexity, harmonic convexity and so on. When $f$ : ${\mathbb{R}}_+{\rightarrow}{\mathbb{R}}$ is defined as $f(x)=(x^m-1)/m$ if $m{\neq}0$ and $f(x)$ = ln $x$ if $m=0$, the necessary and sufficient conditions for $f$-convexity (is called Schur $m$-power convexity) of Gini means are given, which generalize and unify certain known results.
  15. Ozkan, A. Sinan;Keskin, Baki;Cakmak, Yasar 499
    https://doi.org/10.4134/BKMS.2013.50.2.499 PDF KSCI
    The half-inverse spectral problem for an impulsive Sturm-Liouville operator consists in reconstruction of this operator from its spectrum and half of the potential. In this study, the spectrum of the impulsive Sturm-Liouville problem is given and by using the Hochstadt and Lieberman's method we show that if $q(x)$ is prescribed on (0, ${\frac{\pi}{2}}$), then only one spectrum is sufficient to determine $q(x)$ on the interval (0, ${\pi}$) for this problem.
  16. Anvariyeh, Seid Mohammad;Momeni, Somayyeh 507
    https://doi.org/10.4134/BKMS.2013.50.2.507 PDF KSCI
    The notion of $n$-ary algebraic hyperstructures is a generalization of ordinary algebraic hyperstructures. In this paper, we associate an n-ary hypergroupoid (H, $f$) with an ($n+1$)-ary relation ${\rho}_{n+1}$ defined on a non-empty set H. Then, we obtain some basic results in this respect. In particular, we investigate when it is an $n$-ary $H_v$-group, an $n$-ary hypergroup or a join $n$-ary space.
  17. Jeong, Imsoon;Perez, Juan De Dios;Suh, Young Jin 525
    https://doi.org/10.4134/BKMS.2013.50.2.525 PDF KSCI
    In this paper we give a non-existence theorem for Hopf hypersurfaces in the complex two-plane Grassmannian $G_2({\mathbb{C}}^{m+2})$ with re-current normal Jacobi operator ${\bar{R}}_N$.
  18. Kim, Jin Hong 537
    https://doi.org/10.4134/BKMS.2013.50.2.537 PDF KSCI
  19. Kim, Jongtae;Moon, Myoungho 543
    https://doi.org/10.4134/BKMS.2013.50.2.543 PDF KSCI
    Let ${\Gamma}$ be a graph which contains two vertices $a$, $b$ with the same link. For the case where the link has less than 3 vertices, we prove that if the right-angled Artin group A(${\Gamma}$) contains a hyperbolic surface subgroup, then A(${\Gamma}$-{a}) contains a hyperbolic surface subgroup. Moreover, we also show that the same result holds with certain restrictions for the case where the link has more than or equal to 3 vertices.
  20. Hundley, Joseph 559
    https://doi.org/10.4134/BKMS.2013.50.2.559 PDF KSCI
    This paper is motivated by a 2001 paper of Choie and Kim and a 2006 paper of Bump and Choie. The paper of Choie and Kim extends an earlier result of Bol for elliptic modular forms to the setting of Siegel and Jacobi forms. The paper of Bump and Choie provides a representation theoretic interpretation of the phenomenon, and shows how a natural generalization of Choie and Kim's result on Siegel modular forms follows from a natural conjecture regarding ($g$, K)-modules. In this paper, it is shown that the conjecture of Bump and Choie follows from work of Boe. A second proof which is along the lines of the proof given by Bump and Choie in the genus 2 case is also included, as is a similar treatment of the result of Choie and Kim on Jacobi forms.
  21. Araci, Serkan;Acikgoz, Mehmet;Park, Kyoung Ho 583
    https://doi.org/10.4134/BKMS.2013.50.2.583 PDF KSCI
    In this paper, we introduce the $q$-analogue of $p$-adic log gamma functions with weight alpha. Moreover, we give a relationship between weighted $p$-adic $q$-log gamma functions and $q$-extension of Genocchi and Euler numbers with weight alpha.
  22. Luo, Gui-Mei 589
    https://doi.org/10.4134/BKMS.2013.50.2.589 PDF KSCI
    In this paper, we propose a sufficient condition for the existence of solutions to general variational inequality problems (GVI(K, F, $g$)). The condition is also necessary when F is a $g-P^M_*$ function. We also investigate the boundedness of the solution set of (GVI(K, F, $g$)). Furthermore, we show that when F is norm-coercive, the general complementarity problems (GCP(K, F, $g$)) has a nonempty compact solution set. Finally, we establish some existence theorems for (GNCP(K, F, $g$)).
  23. Spiegelhalter, Paul;Zaharescu, Alexandru 601
    https://doi.org/10.4134/BKMS.2013.50.2.601 PDF KSCI
    In [3] and [2], Atanassov introduced the two arithmetic functions $$I(n)=\prod_{p^{\alpha}{\parallel}n}\;p^{1/{\alpha}}\;and\;R(n)=\prod_{p^{\alpha}{\parallel}n}\;p^{{\alpha}-1}$$ called the irrational factor and the restrictive factor, respectively. Alkan, Ledoan, Panaitopol, and the authors explore properties of these arithmetic functions in [1], [7], [8] and [9]. In the present paper, we generalize these functions to a larger class of elements of $PSL_2(\mathbb{Z})$, and explore some of the properties of these maps.
  24. Gao, Qingwu;Yang, Yang 611
    https://doi.org/10.4134/BKMS.2013.50.2.611 PDF KSCI
    In the paper we study the finite-time ruin probability in a general risk model with constant interest force, in which the claim sizes are pairwise quasi-asymptotically independent and arrive according to an arbitrary counting process, and the premium process is a general stochastic process. For the case that the claim-size distribution belongs to the consistent variation class, we obtain an asymptotic formula for the finite-time ruin probability, which holds uniformly for all time horizons varying in a relevant infinite interval. The obtained result also includes an asymptotic formula for the infinite-time ruin probability.
  25. Zhao, Ping;Yang, Mei 627
    https://doi.org/10.4134/BKMS.2013.50.2.627 PDF KSCI
    Let [$n$] = {1, 2, ${\ldots}$, $n$} be ordered in the standard way. The order-preserving full transformation semigroup ${\mathcal{O}}_n$ is the set of all order-preserving singular full transformations on [$n$] under composition. For this semigroup we describe maximal subsemibands, maximal regular subsemibands, locally maximal regular subsemibands, and completely obtain their classification.
  26. Mo, Xiaohuan;Wang, Xiaoyang 639
    https://doi.org/10.4134/BKMS.2013.50.2.639 PDF KSCI
    In this paper, we study Finsler metrics of constant S-curvature. First we produce infinitely many Randers metrics with non-zero (constant) S-curvature which have vanishing H-curvature. They are counterexamples to Theorem 1.2 in [20]. Then we show that the existence of (${\alpha}$, ${\beta}$)-metrics with arbitrary constant S-curvature in each dimension which is not Randers type by extending Li-Shen' construction.
  27. Irani, Yavar;Bahmanpour, Kamal 649
    https://doi.org/10.4134/BKMS.2013.50.2.649 PDF KSCI
    Let R be a commutative Noetherian ring, I an ideal of R and T be a non-zero I-cofinite R-module with dim(T) ${\leq}$ 1. In this paper, for any finitely generated R-module N with support in V(I), we show that the R-modules $Ext^i_R$(T,N) are finitely generated for all integers $i{\geq}0$. This immediately implies that if I has dimension one (i.e., dim R/I = 1), then $Ext^i_R$($H^j_I$(M), N) is finitely generated for all integers $i$, $j{\geq}0$, and all finitely generated R-modules M and N, with Supp(N) ${\subseteq}$ V(I).
  28. He, Yuan;Zhang, Wenpeng 659
    https://doi.org/10.4134/BKMS.2013.50.2.659 PDF KSCI
    In this note, the $q$-extension of the twisted Lerch Euler zeta functions considered by Jang [Bull. Korean Math. Soc. 47 (2010), no. 6, 1181-1188] is further investigated, and the generalized multiplication theorem for the $q$-extension of the twisted Lerch Euler zeta functions is given. As applications, some well-known results in the references are deduced as special cases.
  29. Im, Bokhee;Ryu, Ji-Young 667
    https://doi.org/10.4134/BKMS.2013.50.2.667 PDF KSCI
    Considering a special double-cover Q of the symmetric group of degree 3, we show that a proper non-regular approximate symmetry occurs from its quasigroup homogeneous space. The weak compatibility of any two elements of Q is completely characterized in any such quasigroup homogeneous space of degree 4.
  30. Glazowska, Dorota;Guerrero, Jose Atilio;Matkowski, Janusz;Merentes, Nelson 675
    https://doi.org/10.4134/BKMS.2013.50.2.675 PDF KSCI
    We prove, under some general assumptions, that a generator of any uniformly bounded Nemytskij operator, mapping a subset of space of functions of bounded variation in the sense of Wiener-Young into another space of this type, must be an affine function with respect to the second variable.
  31. Shi, Yanyue;Lu, Yufeng 687
    https://doi.org/10.4134/BKMS.2013.50.2.687 PDF KSCI
    In this note, we completely characterize the reducing subspaces of $T_{{z^N_1}{z^M_2}}$ on $A^2_{\alpha}(D^2)$ where ${\alpha}$ > -1 and N, M are positive integers with $N{\neq}M$, and show that the minimal reducing subspaces of $T_{{z^N_1}{z^M_2}}$ on the unweighted Bergman space and on the weighted Bergman space are different.
  32. Prajapati, Sunil Kumar;Sarma, Ritumoni 697
    https://doi.org/10.4134/BKMS.2013.50.2.697 PDF KSCI
    The function $g{\mapsto}{\zeta}^k_G(g)$ which counts the number of solutions of $x^k=g$ in a finite group G, is not necessarily a character of G. We study this function for the case of dihedral groups and generalized quaternion groups.