• Bulletin of the Korean Mathematical Society
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• v.36 no.3
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• pp.609-619
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• 1999

IN this note we study more about the omitted are for the extremal functions and its {{{{ {π } over {4 } }}}}-property based upon Schiffer's variational method and zBrickman-Wilken's result. we give an example other than the Koebe function which is both a support point of S and the extreme point of HS. Furthermore, we discuss the relations between the support points and the L wner chain.

• Honam Mathematical Journal
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• v.38 no.3
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• pp.495-506
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• 2016

In this paper, we introduce and investigate a new subclass of meromorphic functions associated with a certain integral operator on Hilbert space. For this class, we obtain several properties like the coefficient inequality, extreme points, radii of close-to-convexity, starlikeness and meromorphically convexity and integral transformation. Further, it is shown that this class is closed under convex linear combination.

• Kyungpook Mathematical Journal
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• v.59 no.4
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• pp.651-663
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• 2019

In this paper, we introduce and study a new subclass of p-valent harmonic functions defined by modified operator and obtain the basic properties such as coefficient characterization, distortion properties, extreme points, convolution properties, convex combination and also we apply integral operator for this class.

• Korean Journal of Mathematics
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• v.8 no.2
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• pp.127-134
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• 2000

Motivated by recent work of Uralegaddi and Sarangi[12], we aim at presenting here system study of novel subclass $R_{\alpha}[{\mu},{\beta},{\xi}]$ of prestarlike functions. Further using operators of fractional calculus, we have obtained distortion theorem for $R_{\alpha}[{\mu},{\beta},{\xi}]$. Lastly the extreme points of $R_{\alpha}[{\mu},{\beta},{\xi}]$ are obtained.

• Journal of the military operations research society of Korea
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• v.14 no.1
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• pp.33-41
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• 1988

In Multiple Objective Linear Programming (MOLP), it is well known that efficient solution and weight are correspondent to each other. The purpose of this paper is to study relationships between efficient face and the region of weight in MOLP. It is shown that the regions of weights corresponding to two efficient extreme points are also neighbor if two efficient extreme points are neighbor each other, and that the set of the efficient solutions corresponding to the common part of weight regions is efficient face. Using the above, we present a method to find the efficient solutions corresponding to a given weight and vice versa.

• Journal of the military operations research society of Korea
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• v.13 no.2
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• pp.33-41
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• 1987

In Multiple Objective Linear Programming (MOLP), it is well known that efficient solution and weight are correspondent to each other. The purpose of this paper is to study relationships between efficient face and the region of weight in MOLP. It is shown that the regions of weights corresponding to two efficient extreme points are also neighbor if two efficient extreme points are neighbor each other, and that the set of the efficient solutions corresponding to the common part of weight regions is efficient face. Using the above, we present a method to find the efficient solutions corresponding to a given weight and vice versa.

• Kyungpook Mathematical Journal
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• v.62 no.2
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• pp.229-242
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• 2022

In this paper, we introduce a new subclass of k-uniformly close-to-convex functions with respect to conjugate points. We study characterization, coefficient estimates, distortion bounds, extreme points and radii problems for this class. We also discuss integral means inequality with the extremal functions. Our findings may be related with the previously known results.

• East Asian mathematical journal
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• v.12 no.1
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• pp.85-92
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• 1996

• Korean Journal of Mathematics
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• v.9 no.1
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• pp.45-52
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• 2001

Let A denote the set {$a{\in}M_n{\mid}a{\geq}0$, $tr(a)=1$}, $St(M_n)$ the set of all states on $M_n$, and $PS(M_n)$ the set of all pure states on $M_n$. We show that there are one-to-one correspondences between A and $St(M_n)$, and between the set of all extreme points of A and $PS(M_n)$. We find a necessary and sufficient condition for a state on $M_{n1}{\oplus}{\cdots}{\oplus}M_{nk}$ to be extended to a pure state on $M_{n1}+{\cdots}+_{nk}$.

• Bulletin of the Korean Mathematical Society
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• v.54 no.2
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• pp.417-428
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• 2017

We classify the extreme bilinear forms of the unit ball of the space of bilinear forms on ${\mathbb{R}}^2$ with hexagonal norms.