• Journal of applied mathematics & informatics
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• 제25권1_2호
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• pp.283-291
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• 2007

A simple graph G is said to be fractional n-factor-critical if after deleting any n vertices the remaining subgraph still has a fractional perfect matching. For fractional n-factor-criticality, in this paper, one necessary and sufficient condition, and three sufficient conditions related to maximum matching, complete closure are given.

• 대한수학회지
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• 제34권2호
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• pp.469-481
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• 1997

In this paper we consider TU-cooperative games in the form of characteristic function. We notice that if one uses the necessary and sufficient condition for the core to be not empty in a dual form, it may be used for selecting the final outcome in the core. Using the linear programming approach for constructing the subcore, which is a subset of the core, we represent it in a simple form. We consider reduced games due to Davis-Mashler, Moulin and Funaki and formulate the sufficient conditions for the subcore to be S-consistent.

• 호남수학학술지
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• 제45권2호
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• pp.248-268
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• 2023

As a generalization of conformal semi-invariant submersion, conformal slant submersion and conformal semi-slant submersion, in this paper we study conformal hemi-slant submersion from Kenmotsu manifold onto a Riemannian manifold. The necessary and sufficient conditions for the integrability and totally geodesicness of distributions are discussed. Moreover, we have obtained sufficient condition for a conformal hemi-slant submersion to be a homothetic map. The condition for a total manifold of the submersion to be twisted product is studied, followed by other decomposition theorems.

• Nuclear Engineering and Technology
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• 제27권4호
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• pp.463-469
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• 1995

궤환효과의 지배를 받는 점동특성시스템은 특정 운전조건에서 여러 개의 정상상태해를 가질 수 있다. 점동특성시스템의 다중해 및 비선형시스템의 일반적인 특성과 관련된 이론적 연구를 통하여, 점동특성시스템이 주어진 외부 입력 반응도에 대해 다중의 정상상태해를 갖기 위한 필요충분조건을 얻었다. 즉 정상상태에서의 궤환반응도가 제환변수의 어떤 값에 대해서 'Strictly Monotoruc'이 아니면, 점동특성시스템은 그 값에 대응되는 운전영역에서 다중의 정상상태해를 갖는다. 반면 정상상태에서의 궤환반응도가 궤환변수의 모든 값에 대해서 'Strictly Monotonic' 이면, 점동특성시스템은 항상 하나의 정상상태해를 갖는다.

• Journal of applied mathematics & informatics
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• 제27권1_2호
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• pp.365-374
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• 2009

Under certain conditions, we use augmented Lagrangians to transform a class of generalized semi-infinite min-max problems into common semi-infinite min-max problems, with the same set of local and global solutions. We give two conditions for the transformation. One is a necessary and sufficient condition, the other is a sufficient condition which can be verified easily in practice. From the transformation, we obtain a new first-order optimality condition for this class of generalized semi-infinite min-max problems.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제13권2호
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• pp.101-108
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• 2009

In this paper, we introduce generalized multiobjective fractional programming problem with two kinds of inequality constraints. Kuhn-Tucker sufficient and necessary optimality conditions are given. We formulate a generalized multiobjective dual problem and establish weak and strong duality theorems for an efficient solution under generalized convexity conditions.

• 대한수학회보
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• 제40권4호
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• pp.553-564
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• 2003

We give sufficient coefficient conditions for starlikeness of a class of complex-valued multivalent meromorphic harmonic and orientation preserving functions in outside of the unit disc. These coefficient conditions are also shown to be necessary if the coefficients of the analytic part of the harmonic functions are positive and the coefficients of the co-analytic part of the harmonic functions are negative. We then determine the extreme points, distortion bounds, convolution and convex combination conditions for these functions.

• 대한수학회보
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• 제37권2호
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• pp.291-301
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• 2000

We give sufficient coefficient conditions for a class of meromorphic univalent harmonic functions that are starlike of some order. Furthermore, it is shown that these conditions are also necessary when the coefficients of the analytic part of the function are positive and the coefficients of the co-analytic part of the function are negative. Extreme points, convolution and convex combination conditions for these classes are also determined. Fianlly, comparable results are given for the convex analogue.

• 대한수학회지
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• 제47권1호
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• pp.17-28
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• 2010

In this paper we deal with linear chance-constrained optimization problems, a class of problems which naturally arise in practical applications in finance, engineering, transportation and scheduling, where decisions are made in presence of uncertainty. After giving the deterministic equivalent formulation of a linear chance-constrained optimization problem we construct a conjugate dual problem to it. Then we provide for this primal-dual pair weak sufficient conditions which ensure strong duality. In this way we generalize some results recently given in the literature. We also apply the general duality scheme to a portfolio optimization problem, a fact that allows us to derive necessary and sufficient optimality conditions for it.

• Journal of applied mathematics & informatics
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• 제4권2호
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• pp.563-571
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• 1997

In this paper we define CR(completely reachable), MICR(minimal cyclic refinement)and MACR(maximal cyclic refinement)-Modules. We have obtained equivalent statements for minimal cyclic submodule and maximal cyclic submodule. Also we have obtained necessary and sufficient conditions for a module M with MICR to be cyclic or strongly cyclic.