scholarly journals p -Valent strongly starlike and strongly convex functions connected with linear differential Borel operator

2021 ◽  
Vol 26 (02) ◽  
pp. 137-148
Author(s):  
S. M. El-Deeb ◽  
G. Murugusundaramoorthy ◽  
A. Alburaikan
Author(s):  
Om P. Ahuja ◽  
Halit Orhan

AbstractIn the present investigation we solve Fekete-Szegö problem for the generalized linear differential operator. In particular, our theorems contain corresponding results for various subclasses of strongly starlike and strongly convex functions


2019 ◽  
Vol 9 (4) ◽  
pp. 2367-2378 ◽  
Author(s):  
Mamoru Nunokawa ◽  
Janusz Sokół

Abstract In this paper we show several sufficient conditions for close-to-convex functions to be strongly starlike of some order. The results continue the line of study from the first author’s paper on the order of strong starlikeness of strongly convex functions, (Nunokawa in Proc Japan Acad Ser A 69(7):234–237, 1993). Also it appears an small improvement of a certain classical results of Ch. Pommerenke. As an application, we also derive estimates for the radii of star-likeness for close-to-convex functions.


1996 ◽  
Vol 27 (2) ◽  
pp. 103-109
Author(s):  
R. PARVATHAM ◽  
MILLICENT PREMABAI

In this paper neighbourhoods of strongly convex and strongly starlike function are determined.


2002 ◽  
Vol 30 (9) ◽  
pp. 569-574 ◽  
Author(s):  
Jin-Lin Liu

LetS∗(ρ,γ)denote the class of strongly starlike functions of orderρand typeγand letC(ρ,γ)be the class of strongly convex functions of orderρand typeγ. By making use of an integral operator defined by Jung et al. (1993), we introduce two novel families of strongly starlike functionsSβα(ρ,γ)andCβα(ρ,γ). Some properties of these classes are discussed.


Author(s):  
Young Jae Sim ◽  
Adam Lecko ◽  
Derek K. Thomas

AbstractLet f be analytic in the unit disk $${\mathbb {D}}=\{z\in {\mathbb {C}}:|z|<1 \}$$ D = { z ∈ C : | z | < 1 } , and $${{\mathcal {S}}}$$ S be the subclass of normalized univalent functions given by $$f(z)=z+\sum _{n=2}^{\infty }a_n z^n$$ f ( z ) = z + ∑ n = 2 ∞ a n z n for $$z\in {\mathbb {D}}$$ z ∈ D . We give sharp bounds for the modulus of the second Hankel determinant $$ H_2(2)(f)=a_2a_4-a_3^2$$ H 2 ( 2 ) ( f ) = a 2 a 4 - a 3 2 for the subclass $$ {\mathcal F_{O}}(\lambda ,\beta )$$ F O ( λ , β ) of strongly Ozaki close-to-convex functions, where $$1/2\le \lambda \le 1$$ 1 / 2 ≤ λ ≤ 1 , and $$0<\beta \le 1$$ 0 < β ≤ 1 . Sharp bounds are also given for $$|H_2(2)(f^{-1})|$$ | H 2 ( 2 ) ( f - 1 ) | , where $$f^{-1}$$ f - 1 is the inverse function of f. The results settle an invariance property of $$|H_2(2)(f)|$$ | H 2 ( 2 ) ( f ) | and $$|H_2(2)(f^{-1})|$$ | H 2 ( 2 ) ( f - 1 ) | for strongly convex functions.


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