Showing papers in "Kyungpook Mathematical Journal in 2005"

On a Class of Analytic Functions Related to the Starlike Functions

Abstract: In this paper we discuss a class of analytic functions related to the starlike functions in the unit disk We prove that this class belongs to the class of close-to-convex functions, we obtain the sharp coefficient upper bounds and distortion theorem of this class, we also get the convexity radius of this class

Intuitionistic Fuzzy Bi-ideals of Ordered Semigroups

Abstract: The intuitionistic fuzzification of the notion of a bi-ideal in ordered semigroups is considered. In terms of intuitionistic fuzzy set, conditions for an ordered semigroup to be completely regular is provided. Characterizations of intuitionistic fuzzy bi-ideals in ordered semigroups are given. Using a collection of bi-ideals with additional conditions, an intuitionistic fuzzy bi-ideal is constructed. Natural equivalence relations on the set of all intuitionistic fuzzy bi-ideals of an ordered semigroup are investigated.

Some Topologies Induced by b-open Sets

Abstract: The class of b-open sets in the sense of Andrijevic ((3)), was discussed by El-Atik ((9)) under the name of ,-open sets. This class is closed under arbitrary union. The aim of this paper is to use A-sets and V-sets due to Maki ((15)) some topologies are constructed with the concept of b-open sets. b-A-sets, b-V-sets are the basic concepts introduced and investigated. Moreover, several types of near continuous function based on b-A-sets, b-V-sets are constructed and studied.

First Order Differential Subordinations and Starlikeness of Analytic Maps in the Unit Disc

Abstract: Let be a complex number with ${\Re}\;{\alpha}\;>\;0$. Let the functions f and g be analytic in the unit disc E = {z : |z| and As consequences, we obtain a number of sufficient conditions for star likeness of analytic maps in the unit disc. Here, the symbol ' ' stands for subordination

On Lifting Modules and Weak Lifting Modules

Abstract: We say that a module M is weak lifting if M is supplemented and every supplement submodule of M is a direct summand. The module M is called lifting, if it is weak lifting and amply supplemented. This paper investigates the structure of weak lifting modules and lifting modules having small radical over commutative noetherian rings.

Generalized Transformation Semigroups Whose Sets of Quasi-ideals and Bi-ideals Coincide

Abstract: Let BQ be the class of all semigroups whose bi-ideals are quasi-ideals. It is known that regular semigroups, right [left] simple semigroups and right [left] 0-simple semigroups belong to BQ. Every zero semigroup is clearly a member of this class. In this paper, we characterize when generalized full transformation semigroups and generalized Baer-Levi semigroups are in BQ in terms of the cardinalities of sets.

On Lorentzian fi-Sasakian Manifolds

Abstract: The present paper deals with Lorentzian fi-Sasakian manifolds with confor- mally flat and quasi conformally flat curvature tensor. It is shown that in both cases, the manifold is locally isometric with a sphere S 2 n +1 (c). Further it is shown that an Lorentzian fi-Sasakian manifold with R(X;Y ):C = 0 is locally isometric with a sphere S 2 n +1 (c), where c = fi 2 .

Regular Difference Covers

Abstract: We introduce the concept of what we call "regular difference covers" and prove many nonexistence results and provide some new constructions. Although the techniques employed mirror those used to investigate difference sets, the end results in this new setting are quite different.

On a Normal Contact Metric Manifold

Abstract: We find the expression of the curvature tensor field for a manifold with is endowed with an almost contact structure satisfying the condition (1.7). By using this condition we obtain some properties of the Ricci tensor and scalar curvature (d. Theorem 3.2 and Proposition 3.2).

Some Nonlinear Alternatives in Banach Algebras with Applications II

Abstract: In this paper a nonlinear alternative of Leray-Schauder type is proved in a Banach algebra involving three operators and it is further applied to a functional nonlinear integral equation of mixed type for proving the existence results in Banach algebras under generalized Lipschitz and conditions.

Properties of Topological Ideals and Banach Category Theorem

Abstract: An ideal space is if it has two disjoint subsets We answer the question: If X is I-resolvable, then is , posed by Dontchev, Ganster and Rose We give three generalizations of the well known Banach Category Theorem and deduce the Banach category Theorem as a corollary Characterizations of completely codense ideals and closed sets are given and their properties are discussed

An-annular Complexes in 3-manifolds

Abstract: Given a non-Haken, non Seifert fibred manifold we describe an algorithm that takes 2 (not necessarily distinct) Heegaard surfaces and produces a complex with certain useful properties (Properties 5.1). Our main tool is Rubinstein and Scharlemann's Cerf theoretic work ([5]).

A Note on Potent Elements

Abstract: In this paper, we prove that every exchange ring can be characterized by potent elements Also we extend [10, Theorem 31 and Theorem 41] to quasi-clean rings in which every element is a sum of a potent element and a unit

The Tunnel Number One Knot with Bridge Number Three is a (1, 1)-knot

Abstract: We call K a (1, 1)-knot in M if M is a union of two solid tori glued along their boundary tori and if K intersects each solid torus in a trivial arc for i = 1 and 2. Note that every (1, 1)-knot is a tunnel number one knot. In this article, we determine when a tunnel number one knot is a (1, 1)-knot. In other words, we show that any tunnel number one knot with bridge number 3 is a (1, 1)-knot.

On $(\Phi,\;\Psi)-intuitionistic$ Fuzzy Subgroups

Abstract: Using the belongs to relation and quasi-coincidence with relation (q) between intuitionistic fuzzy points and intuitionistic fuzzy sets, the concept of fuzzy subgroup where , Ware any two of is introduced, and related properties are investigated.

A Note on an Analogous Continued Fraction of Ramanujan

Abstract: We give an integral representation for an analogous continued fraction of Ramanujan, for this we first prove an interesting identity.

Variants of Compactness in Pointfree Topology

Abstract: This paper introduces compactness notions for frames which are expressed in terms of the convergence of suitably specified general filters. It establishes several preservation properties for them as well as their coreflectiveness in the setting of regular frames. Further, it shows that supercompact, compact, and frames can be described by compactness conditions of the present form so that various familiar facts become consequences of these general results. In addition, the Prime Ideal Theorem and the Axiom of Countable Choice are proved to be equivalent to certain conditions connected with the kind of compactness considered here.

Fredholm Type Integral Equations and Certain Polynomials

Abstract: This paper deals with some useful methods of solving the one-dimensional integral equation of Fredholm type. Application of the reduction techniques with a view to inverting a class of integral equation with Lauricella function in the kernel, Riemann-Liouville fractional integral operators as well as Weyl operators have been made to reduce to this class to generalized Stieltjes transform and inversion of which yields solution of the integral equation. Use of Mellin transform technique has also been made to solve the Fredholm integral equation pertaining to certain polynomials and H-functions.

Triangular Normed Fuzzification of (Implicative) Filters in Lattice Implication Algebras

Abstract: We obtain characterizations of T-fuzzy (implicative) filters and some properties of T-product of fuzzy (implicative) filters in lattice implication algebras. We also establish the extension property for T-fuzzy implicative filters.

On Upper and Lower Z-supercontinuous Multifunctions

Abstract: In this paper, we define a multifunction to be upper (lower) Z -supercontinuous if is z-open in X for every open set V of Y. We obtain some characterizations and several properties concerning upper (lower) Z-supercontinuous multifunctions.

Generalizations of V-rings

Abstract: In this paper, we introduce a new notion which we call a generalized weakly ideal. We also investigate characterizations of strongly regular rings with the condition that every maximal left ideal is a generalized weakly ideal. It is proved that R is a strongly regular ring if and only if R is a left GP-V-ring whose every maximal left (right) ideal is a generalized weakly ideal. Furthermore, if R is a left SGPF ring, and every maximal left (right) ideal is a generalized weakly ideal, it is shown that R/ J (R) is strongly regular. Several known results are improved and extended.

Uniform Topology on Hilbert Algebras

Abstract: We use a congruence relation on deductive systems of a Hilbert algebra H, to define a uniform structure on H and investigate the corresponding topology.

On-op-idempotents

Abstract: In this paper, we introduce the concept of op-idempotents. It is shown that every exchange ring can be characterized by op-idempotents

Some Inequalities for Random Variables whose Probability Density Functions are Bounded Using an Improvement of Grüss Inequality

Abstract: Some recent inequalities for expectation and cumulative distribution function are improved.

Oscillation Criteria of Second-order Half-linear Delay Difference Equations

Abstract: In this paper, we will establish some new oscillation criteria for the second order half-linear delay difference equation , where $\gamma\;>\;0$ is a quotient of odd positive integers. Our results in this paper are sharp and improve some of the well known oscillation results in the literature. Some examples are considered to illustrate our main results.

On Prime Near-rings with Generalized $({\sigma},{\tau})-derivations$

Abstract: Let N be a prime left near-ring with multiplicative center Z and f be a generalized associated with d. We prove commutativity theorems in prime near- rings with generalized .

On the Rate of Convergence of Modified Baskakov Type Operators on Functions of Bounded Variation

Abstract: The aim of this paper is to establish the rate of convergence of Baskakov-Durrmeyer operators for bounded variation function. We have given the better estimate over the results due to Guo ([4]), Anial and Teberska ([1]) and Gupta and Srivastava ([8]).

Strongly Solid Varieties and Free Generalized Clones

Abstract: Clones are sets of operations which are closed under composition and contain all projections. Identities of clones of term operations of a given algebra correspond to hyperidentities of this algebra, i.e., to identities which are satisfied after any replacements of fundamental operations by derived operations ([7]). If any identity of .an algebra is satisfied as a hyperidentity, the algebra is called solid ([3]). Solid algebras correspond to free clones. These connections will be extended to so-called generalized clones, to strong hyperidentities and to strongly solid varieties. On the basis of a generalized superposition operation for terms we generalize the concept of a unitary Menger algebra of finite rank ([6]) to unitary Menger algebras with infinitely many nullary operations and prove that strong hyperidentities correspond to identities in free unitary Menger algebras with infinitely many nullary operations.