# Bulletin of the Korean Mathematical Society (B KOREAN MATH SOC)

## Current impact factor: 0.23

## Impact Factor Rankings

2015 Impact Factor | Available summer 2016 |
---|---|

2014 Impact Factor | 0.228 |

2013 Impact Factor | 0.448 |

2012 Impact Factor | 0.388 |

2011 Impact Factor | 0.244 |

2010 Impact Factor | 0.37 |

2009 Impact Factor | 0.272 |

## Impact factor over time

Impact factor

Year

## Additional details

5-year impact | 0.32 |
---|---|

Cited half-life | 6.00 |

Immediacy index | 0.03 |

Eigenfactor | 0.00 |

Article influence | 0.19 |

Other titles | Bulletin of the Korean Mathematical Society, Bulletin of the Korean Mathematical Society |

ISSN | 1015-8634 |

OCLC | 6653234 |

Material type | Periodical |

Document type | Journal / Magazine / Newspaper |

## Publications in this journal

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**ABSTRACT:**Describing the group of units $U(\mathbb{Z}G)$ of the integral group ring $\mathbb{Z}G$, for a finite group $G$, is a classical and open problem. In this note, we show that $U_1(\mathbb{Z}[T \times C_2]) \cong [F_{97} \rtimes F_5] \rtimes [T \times C_2]$, where $T = \langle a, b: a^6 = 1, a^3 = b^2, ba = a^5b \rangle$ and $F_{97}$, $F_5$ are free groups of ranks 97 and 5, respectively.Bulletin of the Korean Mathematical Society 10/2015; - [Show abstract] [Hide abstract]

**ABSTRACT:**We study helicoidal surfaces with the non-degenerate third fundamental form in Minkowski 3-space. In particular, we mainly focus on the study of helicoidal surfaces with light-like axis in Minkowski 3- space. As a result, we classify helicoidal surfaces satisfying an equation in terms of the position vector field and the Laplace operator with respect to the third fundamental form on the surface.Bulletin of the Korean Mathematical Society 09/2015; 52(5):1569-1578. DOI:10.4134/BKMS.2015.52.5.1569 - [Show abstract] [Hide abstract]

**ABSTRACT:**In this paper the notion of Lie derivative of a tensor field T of type (1,1) of real hypersurfaces in complex space forms with respect to the generalized Tanaka-Webster connection is introduced and is called generalized Tanaka-Webster Lie derivative. Furthermore, three dimensional real hypersurfaces in non-flat complex space forms whose generalized Tanaka-Webster Lie derivative of 1) shape operator, 2) structure Jacobi operator coincides with the covariant derivative of them with respect to any vector field X orthogonal to ξ are studied.Bulletin of the Korean Mathematical Society 09/2015; 52(5):1621-1630. DOI:10.4134/BKMS.2015.52.5.1621 - [Show abstract] [Hide abstract]

**ABSTRACT:**Generalized Fibonacci and Lucas sequences (Un) and (Vn) are defined by the recurrence relations Un+1 = PUn+QUn−1and Vn+1 = PVn +QVn−1, n ≥ 1, with initial conditions U0 = 0, U1 = 1 and V0 = 2, V1 = P. This paper deals with Fibonacci and Lucas numbers of the form Un(P,Q) and Vn(P,Q) with the special consideration that P ≥ 3 is odd and Q = −1. Under these consideration, we solve the equations Vn = 5kx2, Vn = 7kx2, Vn = 5kx2±1, and Vn = 7kx2±1 when k | P with k > 1. Moreover, we solve the equations Vn = 5x2 ±1 and Vn = 7x2 ± 1.Bulletin of the Korean Mathematical Society 09/2015; 52(5):1467-1480. DOI:10.4134/BKMS.2015.52.5.1467 - [Show abstract] [Hide abstract]

**ABSTRACT:**A clique-transversal set D of a graph G is a set of vertices of G such that D meets all cliques of G. The clique-transversal number is the minimum cardinality of a clique-transversal set in G. For every cubic graph with at most two bridges, we first show that it has a perfect matching which contains exactly one edge of each triangle of it; by the result, we determine the exact value of the clique-transversal number of line graph of it. Also, we present a sharp upper bound on the clique- transversal number of line graph of a cubic graph. Furthermore, we prove that the clique-transversal number of line graph of a triangle-free graph is at most the chromatic number of complement of the triangle-free graph.Bulletin of the Korean Mathematical Society 09/2015; 52(5):1423-1431. DOI:10.4134/BKMS.2015.52.5.1423 - [Show abstract] [Hide abstract]

**ABSTRACT:**The relative class number Hd(f) of a real quadratic field K = Q(√m) of discriminant d is the ratio of class numbers of Of and OK, where OK denotes the ring of integers of K and Of is the order of conductor f given by Z+fOK. In a recent paper of A. Furness and E. A. Parker the relative class number of Q(√m) has been investigated using continued fraction in the special case when √m has a diagonal form. Here, we extend their result and show that there exists a conductor f of relative class number 1 when the continued fraction of √m is non-diagonal of period 4 or 5. We also show that there exist infinitely many real quadratic fields with any power of 2 as relative class number if there are infinitely many Mersenne primes.Bulletin of the Korean Mathematical Society 09/2015; 52(5):1559-1568. DOI:10.4134/BKMS.2015.52.5.1559 - [Show abstract] [Hide abstract]

**ABSTRACT:**In this paper we investigate the barrellednes of some spaces of X-valued measures, X being a barrelled normed space, and provide examples of non barrelled spaces of bounded linear operators from a Banach space X into a barrelled normed space Y, equipped with the uniform convergence topology.Bulletin of the Korean Mathematical Society 09/2015; 52(5):1579-1586. DOI:10.4134/BKMS.2015.52.5.1579 - [Show abstract] [Hide abstract]

**ABSTRACT:**In this paper, we completely characterize the nontrivial re- ducing subspaces of the Toeplitz operator (Formula presented.) on the Bergman space A2(D2), where N and M are positive integers.Bulletin of the Korean Mathematical Society 09/2015; 52(5):1649-1660. DOI:10.4134/BKMS.2015.52.5.1649 - [Show abstract] [Hide abstract]

**ABSTRACT:**Comonoid, bi-algebra, and Hopf algebra structures are studied within the universal-algebraic context of entropic varieties. Attention focuses on the behavior of setlike and primitive elements. It is shown that entropic Jónsson-Tarski varieties provide a natural universal-algebraic setting for primitive elements and group quantum couples (generaliza tions of the group quantum double). Here, the set of primitive elements of a Hopf algebra forms a Lie algebra, and the tensor algebra on any algebra is a bi-algebra. If the tensor algebra is a Hopf algebra, then the underlying Jónsson-Tarski monoid of the generating algebra is cancella- tive. The problem of determining when the Jónsson-Tarski monoid forms a group is open.Bulletin of the Korean Mathematical Society 09/2015; 52(5):1587-1606. DOI:10.4134/BKMS.2015.52.5.1587 -
##### Article: Semi-convergence of the parameterized inexact Uzawa method for singular saddle point problems

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**ABSTRACT:**In this paper, we provide semi-convergence results of the parameterized inexact Uzawa method with singular preconditioners for solving singular saddle point problems. We also provide numerical exper- iments to examine the effectiveness of the parameterized inexact Uzawa method with singular preconditioners.Bulletin of the Korean Mathematical Society 09/2015; 52(5):1669-1681. DOI:10.4134/BKMS.2015.52.5.166 - Bulletin of the Korean Mathematical Society 09/2015; 52(5):1729-1735. DOI:10.4134/BKMS.2015.52.5.1729
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**ABSTRACT:**In this note we obtain a unique continuation result for the differential inequality |ϑu| ϑ |V u|, where @ = (iϑy + ϑx)/2 denotes the Cauchy-Riemann operator and V (x, y) is a function in L2(R2).Bulletin of the Korean Mathematical Society 09/2015; 52(5):1753-1757. DOI:10.4134/BKMS.2015.52.5.1753 - [Show abstract] [Hide abstract]

**ABSTRACT:**Catenoid and Riemann’s minimal surface are foliated by circles, that is, they are union of circles. In R3, there is no other nonpla- nar example of circle-foliated minimal surfaces. In R4, the graph Gc of w = c/z for real constant c and ζ ∈ C\{0} is also foliated by circles. In this paper, we show that every circle-foliated minimal surface in Rn is either a catenoid or Riemann’s minimal surface in some 3-dimensional Affine subspace or a graph surface Gc in some 4-dimensional Affine subspace. We use the property that Gc is circle-foliated to construct circle-foliated minimal surfaces in S4 and H4.Bulletin of the Korean Mathematical Society 09/2015; 52(5):1433-1443. DOI:10.4134/BKMS.2015.52.5.1433 - [Show abstract] [Hide abstract]

**ABSTRACT:**In this paper, we prove the existence of at least three non-trivial solutions to nonlinear discrete boundary value problems (Formula presented.) involving the discrete p-Laplacian on simple, finite and connected graphs (Formula presented.) with weight ω, where 1 < q < p < ∞. The approach is based on a suitable combine of variational and truncations methods.Bulletin of the Korean Mathematical Society 09/2015; 52(5):1517-1533. DOI:10.4134/BKMS.2015.52.5.1517

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