Abstract
Denote byS * (⌕), (0≤⌕<1), the family consisting of functionsf(z)=z+a 2z2+...+anzn+... that are analytic and starlike of order ⌕, in the unit disc ⋎z⋎<1. In the present article among other things, with very simple conditions on μ, ⌕ andh(z) we prove the f’(z) (f(z)/z)μ−1<h(z) implies f∈S*(⌕). Our results in this direction then admit new applications in the study of univalent functions. In many cases these results considerably extend the earlier works of Miller and Mocanu [6] and others.
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Bazilevič I E, On a case of integrability in quadratures of Loewner-Kurfarev equation,Mat. Sb. 37 (1955) 471–476
Fournier R, On integrals of bounded analytic functions in the closed unit disc,Complex Variables 11 (1989) 125–133
Fournier R The range of a continuous linear functional over a class of functions defined by subordination,Glasgow Math. J. 32 (1990) 381–387
Gasper G, Non-negative sums of consine, ultra spherical and Jocobi polynomials,J. Math. Anal. Appl. 26 (1969) 60–68
Libera R J, Some classes of regular univalent functions,Proc. Am. Math. Soc. 16 (1965) 755–758
Miller S S and Mocanu P T, Differential subordination and inequalities in the complex plane,J. Differ. Equ. 67 (1987) 199–211
Miller S S and Mocanu P T, Marx-Strohhäcker differential subordination systems,Proc. Am. Math. Soc. 99 (1987) 527–534
Ponnusamy S and Karunakaran V, Differential subordination and conformal mappingsComplex Variables 11 (1989) 79–86
Ponnusamy S, Differential subordination and starlike functions,Complex Variables 19 (1992), 185–194
Ponnusamy S and Singh V, Convolution properties of some classes of analytic functions, (submitted)
Robertson M S, Certain classes of starlike functions,Michigan Math. J. 32 (1985) 135–140
Singh V, Univalent functions with bounded derivative in the unit disc,Indian J. Pure Appl. Math. 8 (1977) 1370–1377
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Ponnusamy, S. Differential subordinations concerning starlike functions. Proc. Indian Acad. Sci. (Math. Sci.) 104, 397–411 (1994). https://doi.org/10.1007/BF02863420
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DOI: https://doi.org/10.1007/BF02863420