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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 46, Issue 6 - Nov 2009
Volume 46, Issue 5 - Sep 2009
Volume 46, Issue 4 - Jul 2009
Volume 46, Issue 3 - May 2009
Volume 46, Issue 2 - Mar 2009
Volume 46, Issue 1 - Jan 2009
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1
NONEXISTENCE OF H-CONVEX CUSPIDAL STANDARD FUNDAMENTAL DOMAIN
Yayenie, Omer ;
Bulletin of the Korean Mathematical Society, volume 46, issue 5, 2009, Pages 823~833
DOI : 10.4134/BKMS.2009.46.5.823
Abstract
It is well-known that if a convex hyperbolic polygon is constructed as a fundamental domain for a subgroup of the modular group, then its translates by the group elements form a locally finite tessellation and its side-pairing transformations form a system of generators for the group. Such hyperbolically convex polygons can be obtained by using Dirichlet's and Ford's polygon constructions. Another method of obtaining a fundamental domain for subgroups of the modular group is through the use of a right coset decomposition and we call such domains standard fundamental domains. In this paper we give subgroups of the modular group which do not have hyperbolically convex standard fundamental domain containing only inequivalent cusps.
2
RIDGELET TRANSFORM ON SQUARE INTEGRABLE BOEHMIANS
Roopkumar, Rajakumar ;
Bulletin of the Korean Mathematical Society, volume 46, issue 5, 2009, Pages 835~844
DOI : 10.4134/BKMS.2009.46.5.835
Abstract
The ridgelet transform is extended to the space of square integrable Boehmians. It is proved that the extended ridgelet transform
is consistent with the classical ridgelet transform R, linear, one-to-one, onto and both
,
.1 are continuous with respect to
-convergence as well as
-convergence.
3
PATH-CONNECTED AND NON PATH-CONNECTED ORTHOMODULAR LATTICES
Park, Eun-Soon ; Song, Won-Hee ;
Bulletin of the Korean Mathematical Society, volume 46, issue 5, 2009, Pages 845~856
DOI : 10.4134/BKMS.2009.46.5.845
Abstract
A block of an orthomodular lattice L is a maximal Boolean subalgebra of L. A site is a subalgebra of an orthomodular lattice L of the form S = A
B, where A and B are distinct blocks of L. An orthomodular lattice L is called with finite sites if |A
B| <
for all distinct blocks A, B of L. We prove that there exists a weakly path-connected orthomodular lattice with finite sites which is not path-connected and if L is an orthomodular lattice such that the height of the join-semilattice [ComL]
generated by the commutators of L is finite, then L is pathconnected.
4
PAIR OF (GENERALIZED-)DERIVATIONS ON RINGS AND BANACH ALGEBRAS
Wei, Feng ; Xiao, Zhankui ;
Bulletin of the Korean Mathematical Society, volume 46, issue 5, 2009, Pages 857~866
DOI : 10.4134/BKMS.2009.46.5.857
Abstract
Let n be a fixed positive integer, R be a 2n!-torsion free prime ring and
,
be a pair of generalized derivations on R. If <
> = 0 for all x
R, then
and
are either left multipliers or right multipliers. Let n be a fixed positive integer, R be a noncommutative 2n!-torsion free prime ring with the center
and d, g be a pair of derivations on R. If <
,
>
for all x
R, then d = g = 0. Then we apply these purely algebraic techniques to obtain several range inclusion results of pair of (generalized-)derivations on a Banach algebra.
5
INDEPENDENTLY GENERATED MODULES
Kosan, Muhammet Tamer ; Ozdin, Tufan ;
Bulletin of the Korean Mathematical Society, volume 46, issue 5, 2009, Pages 867~871
DOI : 10.4134/BKMS.2009.46.5.867
Abstract
A module M over a ring R is said to satisfy (P) if every generating set of M contains an independent generating set. The following results are proved; (1) Let
= (
) be a hereditary torsion theory such that
Mod-R. Then every
-torsionfree R-module satisfies (P) if and only if S = R/
(R) is a division ring. (2) Let
be a hereditary pre-torsion class of modules. Then every module in
satisfies (P) if and only if either
= {0} or S = R/
(R) is a division ring, where
(R) =
{I
: R/I
}.
6
ON QB-IDEALS OF EXCHANGE RINGS
Chen, Huanyin ;
Bulletin of the Korean Mathematical Society, volume 46, issue 5, 2009, Pages 873~884
DOI : 10.4134/BKMS.2009.46.5.873
Abstract
We characterize QB-ideals of exchange rings by means of quasi-invertible elements and annihilators. Further, we prove that every
matrix over such ideals of a regular ring admits a diagonal reduction by quasi-inverse matrices. Prime exchange QB-rings are studied as well.
7
CONVERGENCE THEOREMS FOR INVERSE-STRONGLY MONOTONE MAPPINGS AND QUASI-φ-NONEXPANSIVE MAPPINGS
Qin, Xiaolong ; Kang, Shin-Min ; Cho, Yeol-Je ;
Bulletin of the Korean Mathematical Society, volume 46, issue 5, 2009, Pages 885~894
DOI : 10.4134/BKMS.2009.46.5.885
Abstract
In this paper, we consider a hybrid projection algorithm for a pair of inverse-strongly monotone mappings and a quasi-
-nonexpansive mapping. Strong convergence theorems are established in the framework of Banach spaces.
8
HYPERSURFACES OF ALMOST γ-PARACONTACT RIEMANNIAN MANIFOLD ENDOWED WITH SEMI-SYMMETRIC METRIC CONNECTION
Jun, Jae-Bok ; Ahmad, Mobin ;
Bulletin of the Korean Mathematical Society, volume 46, issue 5, 2009, Pages 895~903
DOI : 10.4134/BKMS.2009.46.5.895
Abstract
We define a semi-symmetric metric connection in an almost
-paracontact Riemannian manifold and we consider invariant, non-invariant and anti-invariant hypersurfaces of an almost
-paracontact Riemannian manifold endowed with a semi-symmetric metric connection.
9
ON CERTAIN CLASSES OF MULTIVALENT FUNCTIONS INVOLVING A GENERALIZED DIFFERENTIAL OPERATOR
Selvaraj, Chellian ; Selvakumaran, Kuppathai A. ;
Bulletin of the Korean Mathematical Society, volume 46, issue 5, 2009, Pages 905~915
DOI : 10.4134/BKMS.2009.46.5.905
Abstract
Making use of a generalized differential operator we introduce some new subclasses of multivalent analytic functions in the open unit disk and investigate their inclusion relationships. Some integral preserving properties of these subclasses are also discussed.
10
ISOMORPHISM CLASSES OF GENUS-3 POINTED TRIGONAL CURVES OVER FINITE FIELDS OF CHARACTERISTIC 2
Kang, Pyung-Lyun ; Sun, Sun-Mi ;
Bulletin of the Korean Mathematical Society, volume 46, issue 5, 2009, Pages 917~930
DOI : 10.4134/BKMS.2009.46.5.917
Abstract
We find all distinct representatives of isomorphism classes of genus-3 pointed trigonal curves and compute the number of isomorphism classes of a special class of genus-3 pointed trigonal curves including that of Picard curves over a finite field F of characteristic 2.
11
FOLIATIONS ASSOCIATED WITH PFAFFIAN SYSTEMS
Han, Chong-Kyu ;
Bulletin of the Korean Mathematical Society, volume 46, issue 5, 2009, Pages 931~940
DOI : 10.4134/BKMS.2009.46.5.931
Abstract
Given a system of smooth 1-forms
= (
,...,
) on a smooth manifold
, we give a necessary and sufficient condition for M to be foliated by integral manifolds of dimension n, n
p := m - s, and construct an integrable supersystem (
) by finding additional 1-forms
= (
,...,
). We also give a necessary and sufficient condition for M to be foliated by reduced submanifolds of dimension n, n
p, and construct an integrable subsystem (
,...,
) by finding a system of first integrals
,...,
. The special case n = p is the Frobenius theorem on involutivity.
12
EVERY POLYNOMIAL OVER A FIELD CONTAINING 𝔽
_{16}
IS A STRICT SUM OF FOUR CUBES AND ONE EXPRESSION A
^{2}
+ A
Gallardo, Luis H. ;
Bulletin of the Korean Mathematical Society, volume 46, issue 5, 2009, Pages 941~947
DOI : 10.4134/BKMS.2009.46.5.941
Abstract
Let q be a power of 16. Every polynomial
[t] is a strict sum
. The values of A,B,C,D,E are effectively obtained from the coefficients of P. The proof uses the new result that every polynomial
[t], satisfying the necessary condition that the constant term Q(0) has zero trace, has a strict and effective representation as:
. This improves for such q's and such Q's a result of Gallardo, Rahavandrainy, and Vaserstein that requires three polynomials F,G,H for the strict representation
+F+GH. Observe that the latter representation may be considered as an analogue in characteristic 2 of the strict representation of a polynomial Q by three squares in odd characteristic.
13
DIRAC EIGENVALUES ESTIMATES IN TERMS OF DIVERGENCEFREE SYMMETRIC TENSORS
Kim, Eui-Chul ;
Bulletin of the Korean Mathematical Society, volume 46, issue 5, 2009, Pages 949~966
DOI : 10.4134/BKMS.2009.46.5.949
Abstract
We proved in [10] that Friedrich's estimate [5] for the first eigenvalue of the Dirac operator can be improved when a Codazzi tensor exists. In the paper we further prove that his estimate can be improved as well via a well-chosen divergencefree symmetric tensor. We study the geometric implication of the new first eigenvalue estimates over Sasakian spin manifolds and show that some particular types of spinors appear as the limiting case.
14
A STUDY ON RECTIFYING CURVES IN THE DUAL LORENTZIAN SPACE
Ozbey, Emine ; Oral, Mehmet ;
Bulletin of the Korean Mathematical Society, volume 46, issue 5, 2009, Pages 967~978
DOI : 10.4134/BKMS.2009.46.5.967
Abstract
In this work, we give some characterizations of rectifying curves in dual Lorentzian space. Also, we show that rectifying dual Lorentzian curves can be stated by the aid of dual unit spherical curves.
15
RICCI CURVATURE OF SUBMANIFOLDS OF AN S-SPACE FORM
Kim, Jeong-Sik ; Dwivedi, Mohit Kumar ; Tripathi, Mukut Mani ;
Bulletin of the Korean Mathematical Society, volume 46, issue 5, 2009, Pages 979~998
DOI : 10.4134/BKMS.2009.46.5.979
Abstract
Involving the Ricci curvature and the squared mean curvature, we obtain a basic inequality for a submanifold of an S-space form tangent to structure vector fields. Equality cases are also discussed. As applications we find corresponding results for almost semi-invariant submanifolds,
-slant submanifolds, anti-invariant submanifold and invariant submanifolds. A necessary and sufficient condition for a totally umbilical invariant submanifold of an S-space form to be Einstein is obtained. The inequalities for scalar curvature and a Riemannian invariant
of different kind of submanifolds of a S-space form
are obtained.
16
EIGENVALUE PROBLEMS FOR p-LAPLACIAN DYNAMIC EQUATIONS ON TIME SCALES
Guo, Mingzhou ; Sun, Hong-Rui ;
Bulletin of the Korean Mathematical Society, volume 46, issue 5, 2009, Pages 999~1011
DOI : 10.4134/BKMS.2009.46.5.999
Abstract
In this paper, we are concerned with the following eigenvalue problems of m-point boundary value problem for p-Laplacian dynamic equation on time scales
,
, where
u, p > 1 and
> 0 is a real parameter. Under certain assumptions, some new results on existence of one or two positive solution and nonexistence are obtained for
evaluated in different intervals. Our work develop and improve many known results in the literature even for the continual case. In doing so the usual restriction that
and
exist is removed. As an applications, an example is given to illustrate the main results obtained.
17
OVERRINGS OF THE KRONECKER FUNCTION RING Kr(D, *) OF A PRUFER *-MULTIPLICATION DOMAIN D
Chang, Gyu-Whan ;
Bulletin of the Korean Mathematical Society, volume 46, issue 5, 2009, Pages 1013~1018
DOI : 10.4134/BKMS.2009.46.5.1013
Abstract
Let * be an e.a.b. star operation on an integrally closed domain D, and let
(D, *) be the Kronecker function ring of D. We show that if D is a P*MD, then the mapping
is a bijection from the set {
} of *-linked overrings of D into the set of overrings of
. This is a generalization of [5, Proposition 32.19] that if D is a Pr
fer domain, then the mapping
is a one-to-one mapping from the set {
} of overrings of D onto the set of overrings of
(D, b).
18
THE DISJOINT CURVE PROPERTY AND BRIDGE SURFACES
Hong, Sung-Bok ; Kim, Heoung-Sook ;
Bulletin of the Korean Mathematical Society, volume 46, issue 5, 2009, Pages 1019~1029
DOI : 10.4134/BKMS.2009.46.5.1019
Abstract
We show that every bridge surface of certain types of (1, 1) prime knot has the disjoint curve property. Also we determine when a bridge surface of a pretzel knot of type (.2, 3, n) has the disjoint curve property.
19
POSITIVE LINEAR OPERATORS IN C*-ALGEBRAS
Park, Choon-Kil ; An, Jong-Su ;
Bulletin of the Korean Mathematical Society, volume 46, issue 5, 2009, Pages 1031~1040
DOI : 10.4134/BKMS.2009.46.5.1031
Abstract
It is shown that every almost positive linear mapping h :
of a Banach *-algebra
to a Banach *-algebra
is a positive linear operator when h(rx) = rh(x) (r > 1) holds for all
, and that every almost linear mapping h :
of a unital C*-algebra
to a unital C*-algebra
is a positive linear operator when h(
) = h(
)*h(y) holds for all unitaries
, all
, and all n = 0, 1, 2, ..., by using the Hyers-Ulam-Rassias stability of functional equations. Under a more weak condition than the condition as given above, we prove that every almost linear mapping h :
of a unital C*-algebra
A to a unital C*-algebra
is a positive linear operator. It is applied to investigate states, center states and center-valued traces.