• Title/Summary/Keyword: Nunokawa's Lemma

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SOME RESULTS ASSOCIATED WITH CERTAIN ANALYTIC AND UNIVALENT FUNCTIONS INVOLVING FRACTIONAL DERIVATIVE OPERATORS

  • Irmak, H.;Raina, R.K.
    • East Asian mathematical journal
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    • v.21 no.2
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    • pp.219-231
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    • 2005
  • This paper investigates some results (Theorems 2.1-2.3, below) concerning certain classes of analytic and univalent functions, involving the familiar fractional derivative operators. We state interesting consequences arising from the main results by mentioning the cases connected with the starlikeness, convexity, close-to-convexity and quasi-convexity of geometric function theory. Relevant connections with known results are also emphasized briefly.

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A CRITERION FOR BOUNDED FUNCTIONS

  • Nunokawa, Mamoru;Owa, Shigeyoshi;Sokol, Janusz
    • Bulletin of the Korean Mathematical Society
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    • v.53 no.1
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    • pp.215-225
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    • 2016
  • We consider a sufficient condition for w(z), analytic in ${\mid}z{\mid}$ < 1, to be bounded in ${\mid}z{\mid}$ < 1, where $w(0)=w^{\prime}(0)=0$. We apply it to the meromorphic starlike functions. Also, a certain Briot-Bouquet differential subordination is considered. Moreover, we prove that if $p(z)+zp^{\prime}(z){\phi}(p(z)){\prec}h(z)$, then $p(z){\prec}h(z)$, where $h(z)=[(1+z)(1-z)]^{\alpha}$, under some additional assumptions on ${\phi}(z)$.