Showing papers in "Kyungpook Mathematical Journal in 2011"
TL;DR: In this paper, the authors studied the noton of I-monotonic sequences and proved the decomposition theorem and generalized some of the results on monotonic sequence noton.
Abstract: In this article we study the noton of I-monotonic sequences. We prove the decomposition theorem and generalize some of the results on monotonic sequences. We also introduce I-convergent series and studied some results.
60 citations
TL;DR: In this article, the notion of b -locally open sets, bLO * sets and bLO ** sets in bitopological spaces was introduced and several characterizations and proper ties of these sets were obtained.
Abstract: In this article we introduce the notion of b -locally open sets, bLO * sets, bLO ** sets in bitopological spaces and obtain several characterizations and some proper- ties of these sets.
27 citations
TL;DR: In this paper, a generalization of the class of semicommutative rings is introduced, where a ring R is called central semicommuttative if for any a;b 2 R, ab = 0 implies arb is a central element of R for each r 2 R.
Abstract: In this paper, a generalization of the class of semicommutative rings is inves- tigated. A ring R is called central semicommutative if for any a;b 2 R, ab = 0 implies arb is a central element of R for each r 2 R. We prove that some results on semicommutative rings can be extended to central semicommutative rings for this general settings.
22 citations
TL;DR: In this article, a non-existence theorem for Hopf hypersurfaces M in complex two-plane Grassmannians whose normal Jacobi operator is parallel on the distribution F defined by, where [] = Span{}, = Span {,,, } and,.
Abstract: In this paper we give a non-existence theorem for Hopf hypersurfaces M in complex two-plane Grassmannians whose normal Jacobi operator is parallel on the distribution F defined by , where [] = Span{}, = Span {, , } and , .
19 citations
TL;DR: In this article, it was shown that if M is an R-module and S is a semigroup, then the R(S)-module M(S) has few zero-divisors of size n if and only if Property (A) is a commutative, cancellative and torsion-free monoid.
Abstract: Let M be an R-module and S a semigroup. Our goal is to discuss zero-divisors of the semigroup module M(S). Particularly we show that if M is an R-module and S a commutative, cancellative and torsion-free monoid, then the R(S)-module M(S) has few zero-divisors of size n if and only if the R-module M has few zero-divisors of size n and Property (A).
11 citations
TL;DR: In this article, generalized hypersubstitutions can be extended to a mapping on the set of all terms of type = (2) by using this extension, which forms a monoid.
Abstract: In this paper we consider mappings which map the binary operation symbol f to the term (f) which do not necessarily preserve the arities. We call these mappings generalized hypersubstitutions. Any generalized hypersubstitution can be extended to a mapping on the set of all terms of type = (2). We de ne a binary operation on the set (2) of all generalized hypersubstitutions of type = (2) by using this extension The set (2) together with the identity generalized hypersubstitution which maps f to the term f() forms a monoid. We determine all regular elements of this monoid.
10 citations
TL;DR: In this article, the uniqueness of meromorphic functions when certain non-linear differential polynomials share the same 1-points was studied using the notion of weighted sharing of values.
Abstract: Using the notion of weighted sharing of values we study the uniqueness of meromorphic functions when certain non-linear differential polynomials share the same 1-points. Though the main concern of the paper is to improve a result of Fang (5) but as a consequence of the main result we improve and supplement some former results of Lahiri-Sarkar (16), Fang-Fang(6) et. al.
9 citations
TL;DR: In this article, the convergence of the generalized Chebyshev collocation method is shown to be independent of the chosen collocation points and it is observed how the stability region does depend on the collocations points.
Abstract: The Chebyshev collocation method in [21] to solve stiff initial-value problems is generalized by using arbitrary degrees of interpolation polynomials and arbitrary collocation points The convergence of this generalized Chebyshev collocation method is shown to be independent of the chosen collocation points It is observed how the stability region does depend on collocation points In particular, A-stability is shown by taking the mid points of nodes as collocation points
7 citations
TL;DR: In this paper, the authors consider pseudo-symmetric and Ricci generalized N() contact metric manifolds with the condition that the curvature tensor and the Ricci tensor are equal.
Abstract: We consider pseudo-symmetric and Ricci generalized pseudo-symmetric N() contact metric manifolds. We also consider N()-contact metric manifolds satisfying the condition = 0 where R and S denote the curvature tensor and the Ricci tensor respectively. Finally we give some examples.
6 citations
TL;DR: Differential subordination and superordination results for multivalent meromorphic functions associated with the Liu-Srivastava linear operator in the punctured unit disk were derived by investigating appropriate classes of admissible functions as discussed by the authors.
Abstract: Differential subordination and superordination results are obtained for multivalent meromorphic functions associated with the Liu-Srivastava linear operator in the punctured unit disk. These results are derived by investigating appropriate classes of admissible functions. Sandwich-type results are also obtained.
6 citations
TL;DR: In this article, a right GPF ring and a semiprimitive ring with PS-injectivity are studied and several new properties of right PS injectivity are obtained.
Abstract: . A right ideal I of a ring R is small in case for every proper right ideal Kof R, K + I 6= R. A right R-module M is called PS-injective if every R-homomorphismf : aR ! M for every principally small right ideal aR can be extended to R ! M. A ringR is called right PS-injective if R is PS-injective as a right R-module. We develop, inthis article, PS-injectivity as a generalization of P-injectivity and small injectivity. Manycharacterizations of right PS-injective rings are studied. In light of these facts, we getseveral new properties of a right GPF ring and a semiprimitive ring in terms of rightPS-injectivity. Related examples are given as well. 1. IntroductionThroughout this paper, R is an associative ring with identity and all modulesare unitary. Let R be a ring. The Jacobson radical and nil radical of R are denotedby J(R) and Nil(R), respectively. The right singular ideal is denoted by Z(R R ),the socles are denoted by soc(R R ) and soc( R R). If X is a subset of R, the right(resp. left) annihilator of X in R is denoted by r
TL;DR: In this paper, an at-tempt has been made to establish certain results involving basic bilateral hypergeometric series and continued fractions, making use of transformation due to S. N. Singh.
Abstract: In this paper, making use of transformation due to S. N. Singh [21], an at-tempt has been made to establish certain results involving basic bilateral hypergeometric series and continued fractions.
TL;DR: This paper will construct symmetric links by using the method adapted from the graph theory, and study a Seifert matrix of a symmetric link from the information of the Seifer matrix of the base link and the corresponding group action.
Abstract: In this paper, we will construct symmetric links by using the method adapted from the graph theory, and study a Seifert matrix of a symmetric link from the information of the Seifert matrix of the base link and the corresponding group action.
TL;DR: In this paper, the authors define new classes of analytic functions using a general derivative operator which is a unification of the S˘ al˘ agean derivative operator, the Owa- Srivastava fractional calculus operator and the Al-Oboudi operator.
Abstract: In this paper, we define new classes of analytic functions using a general derivative operator which is a unification of the S˘ al˘ agean derivative operator, the Owa- Srivastava fractional calculus operator and the Al-Oboudi operator, and discuss some coefficient inequalities for functions belong to this classes.
TL;DR: In this paper, it was shown that if a semiprime -ring admits a left-bimultiplier M, then M maps R R into Z(R).
Abstract: In this paper we dene the notions of left -bimultiplier, -bimultiplier and generalized -biderivation, and to prove that if a semiprime -ring admits a left - bimultiplier M, then M maps R R into Z(R). In Section 3, we discuss the applications of theory of -bimultipliers. Further, it was shown that if a semiprime -ring R admits a symmetric generalized -biderivation G : R R ! R with an associated nonzero symmet- ric -biderivation B : R R ! R, then G maps R R into Z(R). As an application, we establish corresponding results in the setting of C -algebra.
TL;DR: In this paper, the uniqueness of nonlinear differential polynomials sharing one value was studied with weighted sharing method, and two uniqueness theorems were proved, one generalizing some recent results in [10] and [16] and the other supplementing a result in [17].
Abstract: In the paper, we study with weighted sharing method the uniqueness of entire functions concerning nonlinear differential polynomials sharing one value and prove two uniqueness theorems, first one of which generalizes some recent results in [10] and [16]. Our second theorem will supplement a result in [17].
TL;DR: In this article, the authors studied integral domains D such that every upper to zero in D[X] contains a prime element (resp., a primary element, a t-invertible primary ideal, an invertible prime ideal).
Abstract: Let D be an integral domain with quotient field K, X be an indeterminate over D, and D[X] be the polynomial ring over D. A prime ideal Q of D[X] is called an upper to zero in D[X] if Q = fK[X] D[X] for some f D[X]. In this paper, we study integral domains D such that every upper to zero in D[X] contains a prime element (resp., a primary element, a t-invertible primary ideal, an invertible primary ideal).
TL;DR: In this paper, the authors show that the "if" part of the assertion fails if P is taken to be the "divided domain" property, which is the case in this paper.
Abstract: Let (R, T) be a normal pair of commutative rings (i.e., R T is a unita extension of commutative rings, not necessarily integral domains, such that S is integrally closed in T for each ring S such that R S T) such that the total quotient ring of R is a von Neumann regular ring. Let P be one of the following ring-theoretic properties: going-down ring, extensionally going-down (EGD) ring, locally divided ring. Then R has P if and only if T has P. An example shows that the "if" part of the assertion fails if P is taken to be the "divided domain" property.
TL;DR: In this article, the authors studied Baer and quasi-Baer modules over some classes of rings and introduced a new class of modules called AI-modules, in which the kernel of every nonzero endomorphism is contained in a proper direct summand.
Abstract: We study Baer and quasi-Baer modules over some classes of rings. We also introduce a new class of modules called AI-modules, in which the kernel of every nonzero endomorphism is contained in a proper direct summand. The main results obtained here are: (1) A module is Baer iff it is an AI-module and has SSIP. (2) For a perfect ring R, the direct sum of Baer modules is Baer iff R is primary decomposable. (3) Every injective R-module is quasi-Baer iff R is a QI-ring.
TL;DR: In this article, the radius of convexity of the integral operator (,,, ;,,, )(z) analytic functions with positive real part when = 1 is determined.
Abstract: In this paper, we introduce the integral operator (, , ; , , )(z) analytic functions with positive real part. The radius of convexity of this integral operator when = 1 is determined. In particular, we get the radius of starlikeness and convexity of the analytic functions with Re {f(z)/z} > 0 and Re {f'(z)} > 0. Furthermore, we derive sufficient condition for the integral operator (, , ; , , )(z) to be analytic and univalent in the open unit disc, which leads to univalency of the operators dt and .
TL;DR: Duality in the optimal harvesting for a nonlinear age-spatial structured pop-up dynamic model is studied in the framework of optimal control problem in this paper, where the duality theory that displays the conjugacy of the primal problem is established and an application is given.
Abstract: Duality in the optimal harvesting for a nonlinear age-spatial structured pop- ulation dynamic model is studied in the framework of optimal control problem. In this paper the duality theory that displays the conjugacy of the primal problem is established and an application is given. Duality theory plays an important role in both optimization theory and methodology and the results may be applied to a realistic biological system on the point of optimal harvesting.
TL;DR: In this paper, the authors give some characterizations of non-existence of light-like hypersurfaces of an indefinite space form, and some geometric objects for the induced Ricci tensor to be symmetric are studied.
Abstract: We give some characterizations of non-existence of lightlike hypersurfaces of an indefinite space form. Some geometric objects for the induced Ricci tensor to be symmetric are studied.
TL;DR: In this article, the authors introduce a partitioning ideal of a ternary semiring, which is useful to develop the quotient structure of the semiring and prove that the quotients of a semiring S/ is essentially independent of choice of Q.
Abstract: In this paper, we introduce a partitioning ideal of a ternary semiring which is useful to develop the quotient structure of ternary semiring. Indeed we prove : 1) The quotient ternary semiring S/ is essentially independent of choice of Q. 2) If f : S S' is a maximal ternary semiring homomorphism, then S/ker S'. 3) Every partitioning ideal is subtractive. 4) Let I be a Q-ideal of a ternary semiring S. Then A is a subtractive ideal of S with I A if and only if A/ = {q + I : q Q A} is a subtractive idea of S/.
TL;DR: In this paper, the radii of -spirallikeness and starlikeness of the -Robert function were determined and the subordination problems related to the -Robertson function were studied.
Abstract: In the present paper, we are concerned with subordination problems related to -Robertson function. The radii of -spirallikeness and starlikeness of -Robert function are also determined.
TL;DR: In this article, the authors improved slightly Curto-Lee's extremal value by using analgorithm and computer software tool and showed that a quartically hyponormal weighted shift which is not 3-hyponormal can be improved.
Abstract: . Examples of a quartically hyponormal weighted shift which is not 3-hyponormal are discussed in this note. In [7] Exner-Jung-Park proved that if (x) :px;q 23 ;q 34 ;q 45 ; with 0
TL;DR: In this article, the definition of a closure operator for a finite matroid was generalized to a pi-space and corresponding closure axioms were obtained, and some properties of pi-spaces were discussed.
Abstract: In this paper, we generalize the definition of a closure operator for a finite matroid to a pi-space and obtain the corresponding closure axioms. Then we discuss some properties of pi-spaces using the closure axioms and prove the non-existence for the dual of a pi-space. We also present some results on the automorphism group of a pi-space.
TL;DR: In this article, it was shown that the space W2 of minimally supported fre- quency wavelets, the supports of whose Fourier transforms consist of two intervals, is path-connected.
Abstract: In this paper, we obtain that the space W2 of minimally supported fre- quency wavelets, the supports of whose Fourier transforms consist of two intervals, is path-connected.
TL;DR: In this article, the authors introduce ($, s)-continuous functions between topological spaces, study some of its basic properties and discuss its relationships with other topological functions, and discuss their relationship with other functions.
Abstract: In this paper, we introduce ($, s)-continuous functions between topological spaces, study some of its basic properties and discuss its relationships with other topological functions.
TL;DR: In this paper, a ring R is called left weakly np injective if, for each non-nilpotent element a of R, there exists a positive integer n such that any left R homomorphism from Ra n to R is right multiplication by an element of R.
Abstract: A ring R is called left weakly np injective if for each non-nilpotent element a of R, there exists a positive integer n such that any left R homomorphism from Ra n to R is right multiplication by an element of R. In this paper various properties of these rings are rst developed, many extending known results such as every left or right module over a left weakly np injective ring is divisible; R is left seft-injective if and only if R is left weakly np-injective and RR is weakly injective; R is strongly regular if and only if R is abelian left pp and left weakly np injective. We next introduce the concepts of left weakly pp rings and left weakly C2 rings. In terms of these rings, we give some characterizations of (von Neumann) regular rings such as R is regular if and only if R is n regular, left weakly pp and left weakly C2. Finally, the relations among left C2 rings, left weakly C2 rings and left GC2 rings are given.
TL;DR: In this paper, the authors introduce and study the sequence spaces ( w, �; F; p; q ) 1(∆ m ), ( w; �;F; p, q, q ) 0( ∆ m ) which arise from the no-tions of generalized difference sequence space, lacunary convergence, invariant mean and a sequence of Moduli F = ( f k).
Abstract: The aim of this paper is to introduce and study the sequence spaces ( w; �; F; p; q ) 1(∆ m ), ( w; �; F; p; q ) 1(∆ m ) and ( w; �; F; p; q ) 0(∆ m ), which arise from the no- tions of generalized difference sequence space, lacunary convergence, invariant mean and a sequence of Moduli F = ( f k). We establish some inclusion relations between these spaces under some conditions.