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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 :
Volume & Issues
Volume 51, Issue 6 - Nov 2014
Volume 51, Issue 5 - Sep 2014
Volume 51, Issue 4 - Jul 2014
Volume 51, Issue 3 - May 2014
Volume 51, Issue 2 - Mar 2014
Volume 51, Issue 1 - Jan 2014
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1
AUTOCOMMUTATORS AND AUTO-BELL GROUPS
Moghaddam, Mohammad Reza R. ; Safa, Hesam ; Mousavi, Azam K. ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 923~931
DOI : 10.4134/BKMS.2014.51.4.923
Abstract
Let x be an element of a group G and be an automorphism of G. Then for a positive integer n, the autocommutator
is defined inductively by
and
. We call the group G to be n-auto-Engel if
for all
and every
, where
. Also, for any integer
, 1, a group G is called an n-auto-Bell group when
for every
and each
. In this paper, we investigate the properties of such groups and show that if G is an n-auto-Bell group, then the factor group
has finite exponent dividing 2n(n-1), where
is the third term of the upper autocentral series of G. Also, we give some examples and results about n-auto-Bell abelian groups.
2
REPRESENTATIONS OF SOLUTIONS TO PERIODIC CONTINUOUS LINEAR SYSTEM AND DISCRETE LINEAR SYSTEM
Kim, Dohan ; Shin, Jong Son ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 933~942
DOI : 10.4134/BKMS.2014.51.4.933
Abstract
We give a representation of the component of solutions with characteristic multiplier 1 in a periodic linear inhomogeneous continuous system. It follows from this representation that asymptotic behaviors of the component of solutions to the system and to its associated homogeneous system are quite different, though they are similar in the case where the characteristic multiplier is not 1. Moreover, the representation is applicable to linear discrete systems with constant coefficients.
3
FINITE GROUPS WITH SOME SEMI-p-COVER-AVOIDING OR ss-QUASINORMAL SUBGROUPS
Kong, Qingjun ; Guo, Xiuyun ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 943~948
DOI : 10.4134/BKMS.2014.51.4.943
Abstract
Suppose that G is a finite group and H is a subgroup of G. H is said to be an ss-quasinormal subgroup of G if there is a subgroup B of G such that G = HB and H permutes with every Sylow subgroup of B; H is said to be semi-p-cover-avoiding in G if there is a chief series 1 =
<
<
<
of G such that, for every i = 1, 2,
, t, if
is a p-chief factor, then H either covers or avoids
. We give the structure of a finite group G in which some subgroups of G with prime-power order are either semi-p-cover-avoiding or ss-quasinormal in G. Some known results are generalized.
4
A NOTE ON TERNARY CYCLOTOMIC POLYNOMIALS
Zhang, Bin ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 949~955
DOI : 10.4134/BKMS.2014.51.4.949
Abstract
Let
denote the n-th cyclotomic polynomial. In this note, let p < q < r be odd primes, where
(mod p) and
(mod pq), we construct an explicit k such that a(pqr, k) = -2.
5
ON THE GEOMETRY OF LORENTZ SPACES AS A LIMIT SPACE
Yun, Jong-Gug ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 957~964
DOI : 10.4134/BKMS.2014.51.4.957
Abstract
In this paper, we prove that there is no branch point in the Lorentz space (M, d) which is the limit space of a sequence {(
)} of compact globally hyperbolic interpolating spacetimes with
-properties and curvature bounded below. Using this, we also obtain that every maximal timelike geodesic in the limit space (M, d) can be expressed as the limit curve of a sequence of maximal timelike geodesics in {(
)}. Finally, we show that the limit space (M, d) satisfies a timelike triangle comparison property which is analogous to the case of Alexandrov curvature bounds in length spaces.
6
L
^{p}
-SOBOLEV REGULARITY FOR INTEGRAL OPERATORS OVER CERTAIN HYPERSURFACES
Heo, Yaryong ; Hong, Sunggeum ; Yang, Chan Woo ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 965~978
DOI : 10.4134/BKMS.2014.51.4.965
Abstract
In this paper we establish sharp
-regularity estimates for averaging operators with convolution kernel associated to hypersurfaces in
of the form
where
and
with
.
7
HALF LIGHTLIKE SUBMANIFOLDS OF AN INDEFINITE TRANS-SASAKIAN MANIFOLD
Jin, Dae Ho ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 979~994
DOI : 10.4134/BKMS.2014.51.4.979
Abstract
We study half lightlike submanifold M of an indefinite trans-Sasakian manifold such that its structure vector field is tangent to M. First we study the general theory for such half lightlike submanifolds. Next we prove some characterization theorems for half lightlike submanifolds of an indefinite generalized Sasakian space form.
8
CERTAIN NEW INTEGRAL FORMULAS INVOLVING THE GENERALIZED BESSEL FUNCTIONS
Choi, Junesang ; Agarwal, Praveen ; Mathur, Sudha ; Purohit, Sunil Dutt ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 995~1003
DOI : 10.4134/BKMS.2014.51.4.995
Abstract
A remarkably large number of integral formulas involving a variety of special functions have been developed by many authors. Also many integral formulas involving various Bessel functions have been presented. Very recently, Choi and Agarwal derived two generalized integral formulas associated with the Bessel function
of the first kind, which are expressed in terms of the generalized (Wright) hypergeometric functions. In the present sequel to Choi and Agarwal's work, here, in this paper, we establish two new integral formulas involving the generalized Bessel functions, which are also expressed in terms of the generalized (Wright) hypergeometric functions. Some interesting special cases of our two main results are presented. We also point out that the results presented here, being of general character, are easily reducible to yield many diverse new and known integral formulas involving simpler functions.
9
BOUNDED COMPOSITION OPERATORS FROM THE BERGMAN SPACE TO THE HARDY SPACE
Kasuga, Kazuhiro ; Nakazi, Takahiko ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1005~1013
DOI : 10.4134/BKMS.2014.51.4.1005
Abstract
Let
be an analytic self map of the open unit disc D. In this paper, we study the composition operator
from the Bergman space on D to the Hardy space on D.
10
ON SOME OPEN PROBLEMS OF MAHMOUDI AND RENSHAW
Qiao, Husheng ; Wei, Chongqing ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1015~1022
DOI : 10.4134/BKMS.2014.51.4.1015
Abstract
This paper continues the investigation of covers of cyclic acts over monoids. Special attention is paid to (P)-covers and strongly flat covers of cyclic acts. In 2008 Mahmoudi and Renshaw posed some open problems and we gave some examples on them in 2012. In this paper, we obtained some further results on these problems and hence gave some deeper answers to them.
11
PARALLEL SECTIONS HOMOTHETY BODIES WITH MINIMAL MAHLER VOLUME IN ℝ
^{n}
Lin, Youjiang ; Leng, Gangsong ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1023~1029
DOI : 10.4134/BKMS.2014.51.4.1023
Abstract
In the paper, we define a class of convex bodies in
-parallel sections homothety bodies, and for some special parallel sections homothety bodies, we prove that n-cubes have the minimal Mahler volume.
12
A NOTE ON CUBICALLY HYPONORMAL WEIGHTED SHIFTS
Li, Chunji ; Cho, Muneo ; Lee, Mi Ryeong ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1031~1040
DOI : 10.4134/BKMS.2014.51.4.1031
Abstract
In this paper, we show that any cubically hyponormal weighted shift with first two equal weights is flat. And we give an example of a weighted shift which is not cubically hyponormal but almost-cubically hyponormal.
13
GENERALIZED FIBONACCI AND LUCAS NUMBERS OF THE FORM wx
^{2}
AND wx
^{2}
∓ 1
Keskin, Refik ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1041~1054
DOI : 10.4134/BKMS.2014.51.4.1041
Abstract
Let
be an integer and let (
) and (
) denote generalized Fibonacci and Lucas sequences defined by
,
;
,
, and
,
for
. In this study, when P is odd, we solve the equations
and
with k | P and k > 1. Then, when k | P and k > 1, we solve some other equations such as
,
,
,
,
, and
. Moreover, when P is odd, we solve the equations
and
for w = 2, 3, 6. After that, we solve some Diophantine equations.
14
GENERATING SETS OF STRICTLY ORDER-PRESERVING TRANSFORMATION SEMIGROUPS ON A FINITE SET
Ayik, Hayrullah ; Bugay, Leyla ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1055~1062
DOI : 10.4134/BKMS.2014.51.4.1055
Abstract
Let
and
denote the order-preserving transformation and the partial order-preserving transformation semigroups on the set
, respectively. Then the strictly partial order-preserving transformation semigroup
on the set
, under its natural order, is defined by
. In this paper we find necessary and sufficient conditions for any subset of SPO(n, r) to be a (minimal) generating set of SPO(n, r) for
.
15
ON MINIMAL NON-𝓠𝓝𝑺-GROUPS
Han, Zhangjia ; Shi, Huaguo ; Chen, Guiyun ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1063~1073
DOI : 10.4134/BKMS.2014.51.4.1063
Abstract
A finite group G is called a
-group if every minimal subgroup X of G is either quasinormal in G or self-normalizing. In this paper the authors classify the non-
-groups whose proper subgroups are all
-groups.
16
ASYMPTOTIC EQUIVALENCE BETWEEN TWO LINEAR DYNAMIC SYSTEMS ON TIME SCALES
Choi, Sung Kyu ; Koo, Namjip ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1075~1085
DOI : 10.4134/BKMS.2014.51.4.1075
Abstract
In this paper we investigate asymptotic properties about asymptotic equilibrium and asymptotic equivalence for linear dynamic systems on time scales by using the notion of
-similarity. Also, we give some examples to illustrate our results.
17
AN ADAPTIVE FINITE DIFFERENCE METHOD USING FAR-FIELD BOUNDARY CONDITIONS FOR THE BLACK-SCHOLES EQUATION
Jeong, Darae ; Ha, Taeyoung ; Kim, Myoungnyoun ; Shin, Jaemin ; Yoon, In-Han ; Kim, Junseok ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1087~1100
DOI : 10.4134/BKMS.2014.51.4.1087
Abstract
We present an accurate and efficient numerical method for solving the Black-Scholes equation. The method uses an adaptive grid technique which is based on a far-field boundary position and the Peclet condition. We present the algorithm for the automatic adaptive grid generation: First, we determine a priori suitable far-field boundary location using the mathematical model parameters. Second, generate the uniform fine grid around the non-smooth point of the payoff and a non-uniform grid in the remaining regions. Numerical tests are presented to demonstrate the accuracy and efficiency of the proposed method. The results show that the computational time is reduced substantially with the accuracy being maintained.
18
CONNECTIONS ON REAL PARABOLIC BUNDLES OVER A REAL CURVE
Amrutiya, Sanjay ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1101~1113
DOI : 10.4134/BKMS.2014.51.4.1101
Abstract
We give analogous criterion to admit a real parabolic connection on real parabolic bundles over a real curve. As an application of this criterion, if real curve has a real point, then we proved that a real vector bundle E of rank r and degree d with gcd(r, d) = 1 is real indecomposable if and only if it admits a real logarithmic connection singular exactly over one point with residue given as multiplication by
. We also give an equivalent condition for real indecomposable vector bundle in the case when real curve has no real points.
19
POINTWISE SLANT SUBMERSIONS
Lee, Jae Won ; Sahin, Bayram ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1115~1126
DOI : 10.4134/BKMS.2014.51.4.1115
Abstract
The purpose of this paper is to study pointwise slant submersions from almost Hermitian manifolds which extends slant submersion in a natural way. Several basic results in this point of view are proven in this paper.
20
NONADDITIVE STRONG COMMUTATIVITY PRESERVING DERIVATIONS AND ENDOMORPHISMS
Zhang, Wei ; Xu, Xiaowei ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1127~1133
DOI : 10.4134/BKMS.2014.51.4.1127
Abstract
Let S be a nonempty subset of a ring R. A map
is called strong commutativity preserving on S if [f(x), f(y)] = [x, y] for all
, where the symbol [x, y] denotes xy - yx. Bell and Daif proved that if a derivation D of a semiprime ring R is strong commutativity preserving on a nonzero right ideal
of R, then
, the center of R. Also they proved that if an endomorphism T of a semiprime ring R is strong commutativity preserving on a nonzero two-sided ideal I of R and not identity on the ideal
, then R contains a nonzero central ideal. This short note shows that the conclusions of Bell and Daif are also true without the additivity of the derivation D and the endomorphism T.
21
FINITE GROUPS ALL OF WHOSE MAXIMAL SUBGROUPS ARE SB-GROUPS
Guo, Pengfei ; Wang, Junxin ; Zhang, Hailiang ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1135~1144
DOI : 10.4134/BKMS.2014.51.4.1135
Abstract
A finite group G is called a SB-group if every subgroup of G is either s-quasinormal or abnormal in G. In this paper, we give a complete classification of those groups which are not SB-groups but all of whose proper subgroups are SB-groups.
22
THE AUTOMORPHISM GROUP OF COMMUTING GRAPH OF A FINITE GROUP
Mirzargar, Mahsa ; Pach, Peter P. ; Ashrafi, A.R. ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1145~1153
DOI : 10.4134/BKMS.2014.51.4.1145
Abstract
Let G be a finite group and X be a union of conjugacy classes of G. Define C(G,X) to be the graph with vertex set X and
(
) joined by an edge whenever they commute. In the case that X = G, this graph is named commuting graph of G, denoted by
. The aim of this paper is to study the automorphism group of the commuting graph. It is proved that Aut(
) is abelian if and only if
;
is of prime power if and only if
, and
is square-free if and only if
. Some new graphs that are useful in studying the automorphism group of
are presented and their main properties are investigated.
23
THE q-DEFORMED GAMMA FUNCTION AND q-DEFORMED POLYGAMMA FUNCTION
Chung, Won Sang ; Kim, Taekyun ; Mansour, Toufik ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1155~1161
DOI : 10.4134/BKMS.2014.51.4.1155
Abstract
In this paper, we rederive the identity
. Then, we give q-analogue of Gauss' multiplication formula and study representation of q-oscillator algebra in terms of the q-factorial polynomials.
24
ON 2-ABSORBING PRIMARY IDEALS IN COMMUTATIVE RINGS
Badawi, Ayman ; Tekir, Unsal ; Yetkin, Ece ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1163~1173
DOI : 10.4134/BKMS.2014.51.4.1163
Abstract
Let R be a commutative ring with
. In this paper, we introduce the concept of 2-absorbing primary ideal which is a generalization of primary ideal. A proper ideal I of R is called a 2-absorbing primary ideal of R if whenever
and
, then
or
or
. A number of results concerning 2-absorbing primary ideals and examples of 2-absorbing primary ideals are given.
25
SELF-DUAL CODES AND FIXED-POINT-FREE PERMUTATIONS OF ORDER 2
Kim, Hyun Jin ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1175~1186
DOI : 10.4134/BKMS.2014.51.4.1175
Abstract
We construct new binary optimal self-dual codes of length 50. We develop a construction method for binary self-dual codes with a fixed-point-free automorphism of order 2. Using this method, we find new binary optimal self-dual codes of length 52. From these codes, we obtain Lee-optimal self-dual codes over the ring
of lengths 25 and 26.
26
WEIGHTED COMPOSITION OPERATORS ON THE MINIMAL MÖBIUS INVARIANT SPACE
Ohno, Shuichi ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1187~1193
DOI : 10.4134/BKMS.2014.51.4.1187
Abstract
We will characterize the boundedness and compactness of weighted composition operators on the minimal M
bius invariant space.
27
VOLUME INTEGRAL MEANS OF HARMONIC FUNCTIONS ON SMOOTH BOUNDARY DOMAINS
Nam, Kyesook ; Park, Inyoung ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1195~1204
DOI : 10.4134/BKMS.2014.51.4.1195
Abstract
We newly define the volume integral means of harmonic functions to characterize the weighted harmonic Bergman spaces. It is based on Xiao and Zhu's results on holomorphic Bergman spaces [5].
28
RELATIVE RELATION MODULES OF FINITE ELEMENTARY ABELIAN p-GROUPS
Yamin, Mohammad ; Sharma, Poonam Kumar ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1205~1210
DOI : 10.4134/BKMS.2014.51.4.1205
Abstract
Let E be a free product of a finite number of cyclic groups, and S a normal subgroup of E such that
is finite. For a prime p,
may be regarded as an
-module via conjugation in E. The aim of this article is to prove that
is decomposable into two indecomposable modules for finite elementary abelian p-groups G.
29
ON THE SOLUTIONS OF THE (λ, n + m)-EINSTEIN EQUATION
Hwang, Seungsu ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1211~1216
DOI : 10.4134/BKMS.2014.51.4.1211
Abstract
In this paper, we study the structure of m-quasi Einstein manifolds when there exists another distinct solution to the (
, n + m)-Einstein equation. In particular, we derive sufficient conditions for the non-existence of such solutions.
30
ON SIMPLE LEFT, RIGHT AND TWO-SIDED IDEALS OF AN ORDERED SEMIGROUP HAVING A KERNEL
Changphas, Thawhat ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1217~1227
DOI : 10.4134/BKMS.2014.51.4.1217
Abstract
The intersection of all two-sided ideals of an ordered semigroup, if it is non-empty, is called the kernel of the ordered semigroup. A left ideal L of an ordered semigroup (
) having a kernel I is said to be simple if I is properly contained in L and for any left ideal L' of (
), I is properly contained in L' and L' is contained in L imply L' = L. The notions of simple right and two-sided ideals are defined similarly. In this paper, the author characterize when an ordered semigroup having a kernel is the class sum of its simple left, right and two-sided ideals. Further, the structure of simple two-sided ideals will be discussed.
31
LARGE SCHRÖDER PATHS BY TYPES AND SYMMETRIC FUNCTIONS
An, Su Hyung ; Eu, Sen-Peng ; Kim, Sangwook ;
Bulletin of the Korean Mathematical Society, volume 51, issue 4, 2014, Pages 1229~1240
DOI : 10.4134/BKMS.2014.51.4.1229
Abstract
In this paper we provide three results involving large Schr
der paths. First, we enumerate the number of large Schr
der paths by type. Second, we prove that these numbers are the coefficients of a certain symmetric function defined on the staircase skew shape when expanded in elementary symmetric functions. Finally we define a symmetric function on a Fuss path associated with its low valleys and prove that when expanded in elementary symmetric functions the indices are running over the types of all Schr
der paths. These results extend their counterparts of Kreweras and Armstrong-Eu on Dyck paths respectively.