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Korean Journal of Mathematics
Journal Basic Information
pISSN :
1976-8605
eISSN :
2288-1433
Journal DOI :
10.11568/kjm
Frequency :
Others
Publisher:
The Kangwon-Kyungki Mathematical Society
Editor in Chief :
Gi-Sang Cheon
Volume & Issues
Volume 23, Issue 4 - Dec 2015
Volume 23, Issue 3 - Sep 2015
Volume 23, Issue 2 - Jun 2015
Volume 23, Issue 1 - Mar 2015
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1
ON THE ANTICYCLOTOMIC ℤ
_{p}
-EXTENSION OF AN IMAGINARY QUADRATIC FIELD
OH, JANGHEON ;
Korean Journal of Mathematics, volume 23, issue 3, 2015, Pages 323~326
DOI : 10.11568/kjm.2015.23.3.323
Abstract
We prove that if a subfield of the Hilbert class field of an imaginary quadratic field k meets the anticyclotomic
-extension
of k, then it is contained in
. And we give an example of an imaginay quadratic field k with
.
2
CONSTRUCTIVE APPROXIMATION BY NEURAL NETWORKS WITH POSITIVE INTEGER WEIGHTS
HONG, BUM IL ; HAHM, NAHMWOO ;
Korean Journal of Mathematics, volume 23, issue 3, 2015, Pages 327~336
DOI : 10.11568/kjm.2015.23.3.327
Abstract
In this paper, we study a constructive approximation by neural networks with positive integer weights. Like neural networks with real weights, we show that neural networks with positive integer weights can even approximate arbitrarily well for any continuous functions on compact subsets of
. We give a numerical result to justify our theoretical result.
3
ON A RING PROPERTY GENERALIZING POWER-ARMENDARIZ AND CENTRAL ARMENDARIZ RINGS
CHA, HO JUN ; JUNG, DA WOON ; KIM, HONG KEE ; KIM, JIN-A ; LEE, CHANG IK ; LEE, YANG ; NAM, SANG BOK ; RYU, SUNG JU ; SEO, YEONSOOK ; SUNG, HYO JIN ; YUN, SANG JO ;
Korean Journal of Mathematics, volume 23, issue 3, 2015, Pages 337~355
DOI : 10.11568/kjm.2015.23.3.337
Abstract
We in this note consider a class of rings which is related to both power-Armendariz and central Armendariz rings, in the spirit of Armendariz and Kaplansky. We introduce central power-Armendariz as a generalization of them, and study the structure of central products of coefficients of zero-dividing polynomials. We also observe various sorts of examples to illuminate the relations between central power-Armendariz and related ring properties.
4
ON (m, n)-IDEALS OF AN ORDERED ABEL-GRASSMANN GROUPOID
YOUSAFZAI, FAISAL ; KHAN, ASAD ; IAMPAN, AIYARED ;
Korean Journal of Mathematics, volume 23, issue 3, 2015, Pages 357~370
DOI : 10.11568/kjm.2015.23.3.357
Abstract
In this paper, we introduce the concept of (m, n)-ideals in a non-associative ordered structure, which is called an ordered Abel-Grassmann's groupoid, by generalizing the concept of (m, n)-ideals in an ordered semigroup [14]. We also study the (m, n)-regular class of an ordered AG-groupoid in terms of (m, n)-ideals.
5
COMPLEX FACTORIZATIONS OF THE GENERALIZED FIBONACCI SEQUENCES {q
_{n}
}
JUN, SANG PYO ;
Korean Journal of Mathematics, volume 23, issue 3, 2015, Pages 371~377
DOI : 10.11568/kjm.2015.23.3.371
Abstract
In this note, we consider a generalized Fibonacci sequence {
}. Then give a connection between the sequence {
} and the Chebyshev polynomials of the second kind
. With the aid of factorization of Chebyshev polynomials of the second kind
, we derive the complex factorizations of the sequence {
}.
6
NONLINEAR BIHARMONIC EQUATION WITH POLYNOMIAL GROWTH NONLINEAR TERM
JUNG, TACKSUN ; CHOI, Q-HEUNG ;
Korean Journal of Mathematics, volume 23, issue 3, 2015, Pages 379~391
DOI : 10.11568/kjm.2015.23.3.379
Abstract
We investigate the existence of solutions of the nonlinear biharmonic equation with variable coefficient polynomial growth nonlinear term and Dirichlet boundary condition. We get a theorem which shows that there exists a bounded solution and a large norm solution depending on the variable coefficient. We obtain this result by variational method, generalized mountain pass geometry and critical point theory.
7
APPROXIMATE ADDITIVE MAPPINGS IN 2-BANACH SPACES AND RELATED TOPICS: REVISITED
YUN, SUNGSIK ;
Korean Journal of Mathematics, volume 23, issue 3, 2015, Pages 393~399
DOI : 10.11568/kjm.2015.23.3.393
Abstract
W. Park [J. Math. Anal. Appl. 376 (2011) 193-202] proved the Hyers-Ulam stability of the Cauchy functional equation, the Jensen functional equation and the quadratic functional equation in 2-Banach spaces. But there are serious problems in the control functions given in all theorems of the paper. In this paper, we correct the statements of these results and prove the corrected theorems. Moreover, we prove the superstability of the Cauchy functional equation, the Jensen functional equation and the quadratic functional equation in 2-Banach spaces under the original given conditions.
8
MAXIMUM ZAGREB INDICES IN THE CLASS OF k-APEX TREES
SELENGE, TSEND-AYUSH ; HOROLDAGVA, BATMEND ;
Korean Journal of Mathematics, volume 23, issue 3, 2015, Pages 401~408
DOI : 10.11568/kjm.2015.23.3.401
Abstract
The first and second Zagreb indices of a graph G are defined as
and
. where
is the degree of the vertex
. G is called a k-apex tree if k is the smallest integer for which there exists a subset X of V (G) such that
= k and G-X is a tree. In this paper, we determine the maximum Zagreb indices in the class of all k-apex trees of order n and characterize the corresponding extremal graphs.
9
STRONG CONVERGENCE OF AN ITERATIVE ALGORITHM FOR A MODIFIED SYSTEM OF VARIATIONAL INEQUALITIES AND A FINITE FAMILY OF NONEXPANSIVE MAPPINGS IN BANACH SPACES
JEONG, JAE UG ;
Korean Journal of Mathematics, volume 23, issue 3, 2015, Pages 409~425
DOI : 10.11568/kjm.2015.23.3.409
Abstract
In this paper, a new iterative scheme based on the extra-gradient-like method for finding a common element of the set of fixed points of a finite family of nonexpansive mappings and the set of solutions of modified variational inequalities in Banach spaces. A strong convergence theorem for this iterative scheme in Banach spaces is established. Our results extend recent results announced by many others.
10
THE JEU DE TAQUIN ON THE SHIFTED RIM HOOK TABLEAUX
LEE, JAEJIN ;
Korean Journal of Mathematics, volume 23, issue 3, 2015, Pages 427~438
DOI : 10.11568/kjm.2015.23.3.427
Abstract
The Schensted algorithm first described by Robinson [5] is a remarkable combinatorial correspondence associated with the theory of symmetric functions.
jeu de taquin[10] can be used to give alternative descriptions of both P- and Q-tableaux of the Schensted algorithm as well as the ordinary and dual Knuth relations. In this paper we describe the jeu de taquin on shifted rim hook tableaux using the switching rule, which shows that the sum of the weights of the shifted rim hook tableaux of a given shape and content does not depend on the order of the content if content parts are all odd.
11
HARMONIC MAPPING RELATED WITH THE MINIMAL SURFACE GENERATED BY ANALYTIC FUNCTIONS
JUN, SOOK HEUI ;
Korean Journal of Mathematics, volume 23, issue 3, 2015, Pages 439~446
DOI : 10.11568/kjm.2015.23.3.439
Abstract
In this paper we consider the meromorphic function G(z) with a pole of order 1 at -a and analytic function F(z) with a zero -a of order 2 in
<
, where -1 < a < 1. From these functions we obtain the regular simply-connected minimal surface
in
and the harmonic function
defined on
, and then we investigate properties of the minimal surface S and the harmonic function f.
12
LIFTABLE OPERATORS ON SOME BANACH SPACES
KANG, JEONGHEUNG ;
Korean Journal of Mathematics, volume 23, issue 3, 2015, Pages 447~456
DOI : 10.11568/kjm.2015.23.3.447
Abstract
In this paper we show that some operators defined on the Banach space with an unconditional basis and
into a Banach space with the RNP have liftable operators.
13
A HYBRID METHOD FOR A SYSTEM INVOLVING EQUILIBRIUM PROBLEMS, VARIATIONAL INEQUALITIES AND NONEXPANSIVE SEMIGROUP
THUY, LE QUANG ; MUU, LE DUNG ;
Korean Journal of Mathematics, volume 23, issue 3, 2015, Pages 457~478
DOI : 10.11568/kjm.2015.23.3.457
Abstract
In this paper we propose an iteration hybrid method for approximating a point in the intersection of the solution-sets of pseudomonotone equilibrium and variational inequality problems and the fixed points of a semigroup-nonexpensive mappings in Hilbert spaces. The method is a combination of projection, extragradient-Armijo algorithms and Manns method. We obtain a strong convergence for the sequences generated by the proposed method.
14
SCIENTIFIC UNDERSTANDING OF THE ANISOTROPIC UNIVERSE IN THE WARPED PRODUCTS SPACETIME FOR AEROSPACE POWER
CHOI, JAEDONG ;
Korean Journal of Mathematics, volume 23, issue 3, 2015, Pages 479~489
DOI : 10.11568/kjm.2015.23.3.479
Abstract
We study the GMGHS spacetime to analyze anisotropic cosmology model which represents homogeneous but anisotropically expanding(contracting)cosmology. In this paper we investigate the solution of GMGHS spacetime in form of doubly warped products possessing warping functions and find the Ricci curvature associated with three phases in the evolution of the universe.
15
ON MARTINGALE PROPERTY OF THE STOCHASTIC INTEGRAL EQUATIONS
KIM, WEONBAE ;
Korean Journal of Mathematics, volume 23, issue 3, 2015, Pages 491~502
DOI : 10.11568/kjm.2015.23.3.491
Abstract
A martingale is a mathematical model for a fair wager and the modern theory of martingales plays a very important and useful role in the study of the stochastic fields. This paper is devoted to investigate a martingale and a non-martingale on the several stochastic integral or differential equations. Specially, we show that whether the stochastic integral equation involving a standard Wiener process with the associated filtration is or not a martingale.