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Bulletin of the Korean Mathematical Society
Journal Basic Information
pISSN :
1015-8634
eISSN :
2234-3016
Journal DOI :
10.4134/BKMS
Frequency :
Others
Publisher:
The Korean Mathematical Society
Editor in Chief :
Yongnam Lee
Volume & Issues
Volume 45, Issue 4 - Nov 2008
Volume 45, Issue 3 - Aug 2008
Volume 45, Issue 2 - May 2008
Volume 45, Issue 1 - Feb 2008
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1
COINCIDENCE POINTS OF WEAKLY COMPATIBLE MAPPINGS
Song, Yisheng ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 607~614
DOI : 10.4134/BKMS.2008.45.4.607
Abstract
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
NEW CHARACTERIZATION OF THE CLASS OF STARLIKE FUNCTIONS
Yavuz, Emel ; Polatoglu, Yasar ; Owa, Shigeyoshi ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 615~620
DOI : 10.4134/BKMS.2008.45.4.615
Abstract
For analytic functions f(z) in the open unit disc
, an operator
relating with starlike functions is introduced. The object of the present paper is to discuss some properties of the operator
.
3
GENERALIZED DERIVATIONS IN PRIME RINGS AND NONCOMMUTATIVE BANACH ALGEBRAS
De Filippis, Vincenzo ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 621~629
DOI : 10.4134/BKMS.2008.45.4.621
Abstract
Let R be a prime ring of characteristic different from 2, C the extended centroid of R, and
a generalized derivations of R. If [[
, x],
] = 0 for all
then either R is commutative or
for all
and some
. We also obtain some related result in case R is a Banach algebra and
is either continuous or spectrally bounded.
4
A CHARACTERIZATION OF PARABOLA
Yu, Yanhua ; Liu, Huili ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 631~634
DOI : 10.4134/BKMS.2008.45.4.631
Abstract
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
ON THE ON THE CONVERGENCE BETWEEN THE MANN ITERATION AND ISHIKAWA ITERATION FOR THE GENERALIZED LIPSCHITZIAN AND Φ-STRONGLY PSEUDOCONTRACTIVE MAPPINGS
Xue, Zhiqun ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 635~644
DOI : 10.4134/BKMS.2008.45.4.635
Abstract
In this paper, we prove that the equivalence between the convergence of Mann and Ishikawa iterations for the generalized Lipschitzian and
-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
ORBITAL SHADOWING PROPERTY
Honary, Bahman ; Bahabadi, Alireza Zamani ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 645~650
DOI : 10.4134/BKMS.2008.45.4.645
Abstract
Let M be a generalized homogeneous compact space, and let Z(M) denotes the space of homeomorphisms of M with the
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
THE SEMIGROUPS OF BINARY SYSTEMS AND SOME PERSPECTIVES
Kim, Hee-Sik ; Neggers, Joseph ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 651~661
DOI : 10.4134/BKMS.2008.45.4.651
Abstract
Given binary operations "*" and "
" on a set X, define a product binary operation "
" as follows:
. This in turn yields a binary operation on Bin(X), the set of groupoids defined on X turning it into a semigroup (Bin(X),
)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
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
ON THE NUMERICAL SOLUTION OF NEUTRAL DELAY DIFFERENTIAL EQUATIONS USING MULTIQUADRIC APPROXIMATION SCHEME
Vanani, Solat Karimi ; Aminataei, Azim ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 663~670
DOI : 10.4134/BKMS.2008.45.4.663
Abstract
In this paper, the aim is to solve the neutral delay differential equations in the following form using multiquadric approximation scheme, (1)
where f :
is a smooth function,
and
are continuous functions on
such that t-
<
and t -
<
. Also
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
COMMON FIXED POINT AND INVARIANT APPROXIMATION IN MENGER CONVEX METRIC SPACES
Hussain, Nawab ; Abbas, Mujahid ; Kim, Jong-Kyu ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 671~680
DOI : 10.4134/BKMS.2008.45.4.671
Abstract
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
TRANS-SEPARABILITY IN THE STRICT AND COMPACT-OPEN TOPOLOGIES
Khan, Liaqat Ali ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 681~687
DOI : 10.4134/BKMS.2008.45.4.681
Abstract
We give a characterization of trans-separability for the function spaces (
,
), (C(X, E), k) and (
, u) in the case of E any general topological vector space.
11
ON Φ-RECURRENT (k, μ)-CONTACT METRIC MANIFOLDS
Jun, Jae-Bok ; Yildiz, Ahmet ; De, Uday Chand ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 689~700
DOI : 10.4134/BKMS.2008.45.4.689
Abstract
In this paper we prove that a
-recurrent (k,
)-contact metric manifold is an
-Einstein manifold with constant coefficients. Next, we prove that a three-dimensional locally
-recurrent (k,
)-contact metric manifold is the space of constant curvature. The existence of
-recurrent (k,
)-manifold is proved by a non-trivial example.
12
ON f-DERIVATIONS OF LATTICES
Ceven, Yilmaz ; Ozturk, Mehmet Ali ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 701~707
DOI : 10.4134/BKMS.2008.45.4.701
Abstract
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
ON SOME RING CLASS FIELDS BY SHIMURA'S CANONICAL MODELS
Choi, So-Young ; Koo, Ja-Kyung ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 709~715
DOI : 10.4134/BKMS.2008.45.4.709
Abstract
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)
N or (a/N, N)
1 for a positive integer N > 1.
14
A GENERAL VISCOSITY APPROXIMATION METHOD OF FIXED POINT SOLUTIONS OF VARIATIONAL INEQUALITIES FOR NONEXPANSIVE SEMIGROUPS IN HILBERT SPACES
Plubtieng, Somyot ; Wangkeeree, Rattanaporn ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 717~728
DOI : 10.4134/BKMS.2008.45.4.717
Abstract
Let H be a real Hilbert space and S = {T(s) :
<
} be a nonexpansive semigroup on H such that
For a contraction f with coefficient 0 <
< 1, a strongly positive bounded linear operator A with coefficient
> 0. Let 0 <
<
. It is proved that the sequences {
} and {
} generated by the iterative method
and
where {t}, {
}
(0, 1) and {
}, {
} are positive real divergent sequences, converges strongly to a common fixed point
which solves the variational inequality
for
.
15
ON MULTI-JENSEN FUNCTIONS AND JENSEN DIFFERENCE
Cieplinski, Krzysztof ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 729~737
DOI : 10.4134/BKMS.2008.45.4.729
Abstract
In this paper we characterize multi-Jensen functions f :
, where n is a positive integer, V, W are commutative groups and V is uniquely divisible by 2. Moreover, under the assumption that f :
is Borel measurable, we obtain representation of f (respectively, f, g, h :
) such that the Jensen difference
(respectively, the Pexider difference
takes values in a countable subgroup of
.
16
ON THE STABILITY OF A GENERALIZED CUBIC FUNCTIONAL EQUATION
Koh, Hee-Jeong ; Kang, Dong-Seung ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 739~748
DOI : 10.4134/BKMS.2008.45.4.739
Abstract
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
for a positive integer
.
17
FUZZY ω
^{O}
-OPEN SETS
Al-Hawary, Talal ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 749~755
DOI : 10.4134/BKMS.2008.45.4.749
Abstract
In this paper, we introduce the relatively new notion of fuzzy
-open set. We prove that the collection of all fuzzy
-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
A NOTE ON LOWER RADICALS OF HEMIRINGS
Zulfiqar, Muhammad ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 757~762
DOI : 10.4134/BKMS.2008.45.4.757
Abstract
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
OSTROWSKI TYPE INEQUALITY FOR ABSOLUTELY CONTINUOUS FUNCTIONS ON SEGMENTS IN LINEAR SPACES
Kikianty, Eder ; Dragomir, Sever S. ; Cerone, Pietro ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 763~780
DOI : 10.4134/BKMS.2008.45.4.763
Abstract
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
ADAPTIVE MESH REFINEMENT FOR WEIGHTED ESSENTIALLY NON-OSCILLATORY SCHEMES
Yoon, Dae-Ki ; Kim, Hong-Joong ; Hwang, Woon-Jae ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 781~795
DOI : 10.4134/BKMS.2008.45.4.781
Abstract
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
AN ANDERSON'S THEOREM ON NONCOMMUTATIVE RINGS
Huh, Chan ; Kim, Nam-Kyun ; Lee, Yang ;
Bulletin of the Korean Mathematical Society, volume 45, issue 4, 2008, Pages 797~800
DOI : 10.4134/BKMS.2008.45.4.797
Abstract
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.