Showing papers in "Kyungpook Mathematical Journal in 2003"

Ricci Tensor in 3-dimensional Trans-Sasakian manifolds

Abstract: In a 3-dimensional trans-Sasakian manifold, explicit formulae for Ricci operator, Ricci tensor and curvature tensor are obtained. In particular, expressions for Ricci tensor are obtained in a 3-dimensional trans-Sasakian manifold in cases of the manifold being η-Einstein or satisfying R (X, Y) · S = 0.

On Lorentzian Almost Paracontact Manifolds with a Structure of the Concircular Type

Abstract: This paper presents a study of Lorentzian almost paracontact manifolds with a structure of the concircular type.

Some Further Results on Meromorphic Functions that Share Two Sets

Abstract: This paper deals with the problem of uniqueness of meromorphic functions that share two sets, and obtain one set S with n(≥ 8) elements such that any two nonconstant meromorphic functions f and g satisfying (S, f) = (S, g), E(∞, f)=E(∞, g) and m≥2, m+n≥11 must be identical.

Some Geometric Properties of Cesaro Sequence Space

Abstract: In this paper we define a modular on the Cesaro sequence sapce ces(p) and consider it equipped with the Luxemburg norm We give some relationships between the modular and the Luxemburg norm on this space and show that the space ces(P) has property (H) but it is not rotund (R), where p = () is a bounded sequence of positive real number with ≥ 1 for all k ∈ N

On θ-Semigeneralized Closed Sets in Topology

Abstract: Levine [17] introduced and investigated the notion of generalized closed set. It is the object of this paper to offer a new notion of generalized closed set called θ-semigeneralized closed set and study its fundamental properties

Some Applications of Certain Integral Operator

Abstract: In this paper we introduce and study some new subclasses of starlike, convex, close-to-convex and quasi-convex functions defined by certain integral operator. Inclusion relations are established and integral operator of functions in these subclasses is discussed.

On ＼N, Pn;δ＼k Summability Factors

Abstract: In this paper a generl theorem on ? summability factors, which generalzies a theorem of Mazhar [6] on ? summability factors, has been proved.

Some limits of the colored Jones polynomials of the figure-eight knot

Abstract: We will study the asymptotic behaviors of the colored Jones polynomials of the figure-eight knot. In particular we will show that for certain limits we obtain the volumes of the cone manifolds with singularities along the knot.

Commutative Group Algebras of Direct Sums of -Summables Abelian p-Groups

Abstract: Suppose G is an abelian group with p-primary component and F is a field of charF = p > 0. The main goal, motivating the present paper, is to show that if G is a direct sum of groups whose p-components are of countable lengths direct sums of countable groups, then is a direct factor of the group S(FG) of all normed p-units in the group algebra FG with a direct sum of countables complementary factor or equivalently is a direct sum of countables. In particular, when G is p-mixed, it is proved that G is a direct factor of the group V(FG) of all normalized units in FG with a direct sum of p-countables complementary factor or in other words V(FG)/G is a direct sum of p-countables. Moreover, for an arbitrary group H the F-isomorphism implies that , and that there exists a direct sum of p-countables T with the property that provided G is p-mixed. These facts on the group structure and on the isomorphism problem generalize statements due to Hill-Ullery (Commun. Algebra, 1997) and to the author (Compt. rend. Acad. bulg. Sci., 1995 and Hokkaido Math. .J., 2000). Besides, the claims on the isomorphism partially settle a question raised by May (Proc. Amer. Math. Soc., 1988) and extend an other author's result in this theme (Proc. Amer. Math. Soc., 1997).

On Perturbed Mid-point and Trapezoid Inequalities and Applications

Abstract: An improvement of perturbed trapezoid inequality is derived. Some related results for the mid-point and trapezoid inequalities are established. Applications in numerical integration are also given.

A Constructive View of Complete Regularity

Abstract: This note introduced the largest interpolative relation contained in the rather below(= well inside) relation in a frame as a constructive version of the familiar completely below (= really inside) relation. It establishes severla constructively valid results for this whose analogues for the latter are only proved by means of the Axiom of Countable Dependent Choice.

On a Class of p-valent Analytic Functions with Complex Order

Abstract: In the present paper, the authors introduce a general class (A, B, p) of p-valent analytic functions in the open unit disk A sufficient condition, coefficient inequalities, distortion theorems and Hadamard product (or convolution) properties of functions belonging to this class are obtained

Chen's Basic Equalities for Submanifolds of Sasakian Space Form

Abstract: We study n(≥3) - dimensional submanifolds of Sasakian space which satisfying Chen's basic equalities and specially improve the Kim-Kim's result about the submanifold of a Sasakian space form satisfying Chen's basic equality about .

Oscillation Criteria for a Class of Parabolic Equations with Functional Arguments

Abstract: Parabolic equations with functional arguments are studied, and sufficient conditions are obtained for the oscillation of solutions of nonlinear parabolic equations. Our approach is to reduce the multi-dimensional problem to a one-dimensional problem for sublinear functional differential inequalities.

On the Type Number of Six-dimensional Planar Hermitian Submanifolds of Cayley Algebra

Abstract: It is proved that the type number of a six-dimensional planar Hermitian submanifold of Cayley algebra is at most two.

The Semicontinuous Quasi-uniformity of a Frame

Abstract: The semicontinuous quasi-uniformity is known to be one of the most im- portant examples of transitive quasi-uniformities. The aim of this paper is to show that various facts in classical topology connected with the semicontinuous quasi-uniformity and semicontinuous real functions may be easily extended to pointfree topology via a construc- tion introduced by the authors in a previous paper. Several consequences are derived. In a previous paper (3), we established a method of constructing transitive compatible quasi-uniformities for an arbitrary frame, extending classical results of Fletcher for quasi-uniform spaces (4). This note is a sequel to (3), which ended with the observation that, starting with the collection of all spectrum covers of a frame, one gets, via that construction, the so called semicontinuous quasi-uniformity of the frame. The present note aims to prove it. For this, we need to look at the frame analogue of semicontinuous real functions. The familiar adjointness between functors O : Top ! Frm and § : Frm ! Top gives us a natural isomorphism

Second Method of Lyapunov for Existence of Almost Periodic Solutions for Impulsive Integro-Differential Equations

Abstract: In the present paper sufficient conditions for the existence of almost periodic solutions of impulsive integro-differential equations are obtained. The investigations are carried out by means piecewise continuous functions which are generalizations of the classical Lyapunov functions and the comparison principle.

A Note on Parakahlerian Manifolds

Abstract: The famous American mathematician Alfred Gray has noted that the identities satisfied by the Riemannian curvature tensor of almost Hermitian manifolds are very important for the study of the geometry of such manifolds [5]. In accordance with this fact, some classes of almost Hermitian manifolds were distinguished. The following identities characterize these classes [5]:

A Note on Harmonic Forms on a Contact Manifold

Abstract: We study the harmonic theory on a contact manifold in terms of the canonical measure associated to the contact form.i

Some BQ-semigroups of Linear Transformations

Abstract: A BQ-semigroups is a semigroup whose sets of bi-ideals and quasi-ideals coincide. In this paper, some linear transformations semigroups on a vector space V over a division ring are characterized in terms of dimV when they are BQ-semigroup.

Bounded Traveling Wave Solution of a Nonlinear Equation

Abstract: Bifurcation method of dynamical systems is applied to investigate traveling waves of nonlinear equation

Certain cs-Images of Locally Separable Metric Spaces

Abstract: In this paper, we describe the closed cs-images of locally separable metric spaces, and characterize some sequence-covering cs-images and compact-covering cs-images of locally separable metric spaces.

Direct Sums of Extending Modules

Abstract: Let M and N be left R-modules. N is called M-ep-injective if N is essentially M-injective and pseudoly M-injective. An example is given to show that M-ep-injectivity is a non-trivial generalization of M-injectivity. We show that any direct sum of relatively ep-injective extending left R-modules of finite length is special extending. It is also proved that the direct sum M=ⓧi∈I of left R-modules (i∈I, I≥2) is extending if and only if there exist i ≠ j in I such that every closed submodule K of M with K ∩ K or K ∩ K or K ∩ = K ∩ = 0 is a direct summand

Semi-invariant Submanifolds with L-flat Normal Connection in terms of the Lie Derivatives

Abstract: We study a semi-invariant submanifold of codimention 3 with L-flat normal connection in a complex projective space, and classify the submanifold above satisfying A=0 or S=0, where A, S and denote by the shape operator in the direction of the distinguished normal, and Ricci tensor of the submanifold and the operator of the Lie derivative with respect to the structure vector e respectively.

Limit Distribution for Sums of the Reciprocals of Sine of Random Variables

Abstract: Let () be a sequence of independent continuous random variables such that sin ≠ 0 for every n. In this paper, we give conditions that the sequence of distribution functions of the reciprocals of sin weakly converges to a limit.