• 제목/요약/키워드: harmonic functions

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TOEPLITZ OPERATORS ON HARMONIC BERGMAN FUNCTIONS ON HALF-SPACES

  • Yi, HeungSu
    • Korean Journal of Mathematics
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    • 제7권2호
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    • pp.271-280
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    • 1999
  • We study Toeplitz operators on the harmonic Bergman Space $b^p(\mathbf{H})$, where $\mathbf{H}$ is the upper half space in $\mathbf{R}(n{\geq}2)$, for 1 < $p$ < ${\infty}$. We give characterizations for the Toeplitz operators with positive symbols to be bounded.

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On A Subclass of Harmonic Multivalent Functions Defined by a Certain Linear Operator

  • Darwish, Hanan Elsayed;Lashin, Abdel Moneim Yousof;Sowileh, Suliman Mohammed
    • Kyungpook Mathematical Journal
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    • 제59권4호
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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.

MEROMOR0PHIC UNIVALENT HARMONIC FUNCTIONS WITH NEGATIVE COEFFICIENTS

  • Jahangiri, Jay M.;Silverman, Herb
    • 대한수학회보
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    • 제36권4호
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    • pp.763-770
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    • 1999
  • The purpose of this paper is to give sufficient coefficient conditions for a class of univalent harmonic functions that map each $$\mid$z$\mid$$ = r >1 onto a curve that bounds a domain that is starlike with respect to origin. Furthermore, it is shown that these conditions are also necessary when the coefficients are negative. Extreme points for these classes are also determined. Finally, comparable results are given for the convex analgo.

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HARMONIC MEROMORPHIC STARLIKE FUNCTIONS

  • Jahangiri, Jay, M.
    • 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.

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A GENERALIZED CLASS OF HARMONIC UNIVALENT FUNCTIONS ASSOCIATED WITH AL-OBOUDI OPERATOR INVOLVING CONVOLUTION

  • Sangle, N.D.;Metkari, A.N.;Joshi, S.B.
    • Nonlinear Functional Analysis and Applications
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    • 제26권5호
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    • pp.887-902
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    • 2021
  • In this paper, we have introduced a generalized class SiH (m, n, 𝛾, 𝜙, 𝜓; 𝛼), i ∈ {0, 1} of harmonic univalent functions in unit disc 𝕌, a sufficient coefficient condition for the normalized harmonic function in this class is obtained. It is also shown that this coefficient condition is necessary for its subclass 𝒯 SiH (m, n, 𝛾, 𝜙, 𝜓; 𝛼). We further obtained extreme points, bounds and a covering result for the class 𝒯 SiH (m, n, 𝛾, 𝜙, 𝜓; 𝛼). Also, show that this class is closed under convolution and convex combination. While proving our results, certain conditions related to the coefficients of 𝜙 and 𝜓 are considered, which lead to various well-known results.

HARMONIC CURVATURE FUNCTIONS OF SOME SPECIAL CURVES IN GALILEAN 3-SPACE

  • Yilmaz, Beyhan;Metin, Seyma;Gok, Ismail;Yayli, Yusuf
    • 호남수학학술지
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    • 제41권2호
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    • pp.301-319
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    • 2019
  • The aim of the paper is to characterize some curves with the help of their harmonic curvature functions. First of all, we have defined harmonic curvature function of an arbitrary curve and have re-determined the position vectors of helices in terms of their harmonic curvature functions in Galilean 3-space. Then, we have investigated the relation between rectifying curves and Salkowski (or anti-Salkowski) curves in Galilean 3-space. Furthermore, the position vectors of them are obtained via the serial approach of the curves. Finally, we have given some illustrated examples of helices and rectifying curves with some assumptions.