• Title/Summary/Keyword: Convex functions

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A NOTE ON PRECONVEXITY SPACES

  • Min, Won-Keun
    • Honam Mathematical Journal
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    • v.29 no.4
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    • pp.589-595
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    • 2007
  • In this paper, we introduce the concepts of the convexity hull and co-convex sets on preconvexity spaces. We study some properties for the co-convexity hull and characterize c-convex functions and c-concave functions by using the co-convexity hull and the convexity hull.

s-CONVEX FUNCTIONS IN THE THIRD SENSE

  • Kemali, Serap;Sezer, Sevda;Tinaztepe, Gultekin;Adilov, Gabil
    • Korean Journal of Mathematics
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    • v.29 no.3
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    • pp.593-602
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    • 2021
  • In this paper, the concept of s-convex function in the third sense is given. Then fundamental characterizations and some basic algebraic properties of s-convex function in the third sense are presented. Also, the relations between the third sense s-convex functions according to the different values of s are examined.

COEFFICIENT BOUNDS FOR CLOSE-TO-CONVEX FUNCTIONS ASSOCIATED WITH VERTICAL STRIP DOMAIN

  • Bulut, Serap
    • Communications of the Korean Mathematical Society
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    • v.35 no.3
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    • pp.789-797
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    • 2020
  • By considering a certain univalent function in the open unit disk 𝕌, that maps 𝕌 onto a strip domain, we introduce a new class of analytic and close-to-convex functions by means of a certain non-homogeneous Cauchy-Euler-type differential equation. We determine the coefficient bounds for functions in this new class. Relevant connections of some of the results obtained with those in earlier works are also provided.

Some Inclusion Properties of New Subclass of Starlike and Convex Functions associated with Hohlov Operator

  • Sokol, Janusz;Murugusundaramoorthy, Gangadharan;Kothandabani, Thilagavathi
    • Kyungpook Mathematical Journal
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    • v.56 no.2
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    • pp.597-610
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    • 2016
  • For a sufficiently adequate special case of the Dziok-Srivastava linear operator defined by means of the Hadamard product (or convolution) with Srivastava-Wright convolution operator, the authors investigate several mapping properties involving various subclasses of analytic and univalent functions, $G({\lambda},{\alpha})$ and $M({\lambda},{\alpha})$. Furthermore we discuss some inclusion relations for these subclasses to be in the classes of k-uniformly convex and k-starlike functions.

ON UNIVALENT SUBORDINATE FUNCTIONS

  • Park, Suk-Joo
    • The Pure and Applied Mathematics
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    • v.3 no.2
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    • pp.103-111
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    • 1996
  • Let $f(z)=z+\alpha_2 z^2$+…+ \alpha_{n}z^n$+… be regular and univalent in $\Delta$ = {z : │z│<1}. In this paper, using the proper subordinate functions, we investigate the some relations between subordinations and conditions of functions belonging to subclasses of univalent functions.

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