scholarly journals Generalized Alpha-Close-to-Convex Functions

Author(s):  
K. Inayat Noor ◽  
Halit Orhan ◽  
Saima Mustafa

We define the classesGβ(α,k,γ)as follows:f∈Gβ(α,k,γ)if and only if, forz∈E={z∈ℂ:|z|<1},|arg{(1-α2z2)f′(z)/e−iβϕ′(z)}|≤γπ/2,0<γ≤1;α∈[0,1];β∈(−π/2,π/2), whereϕis a function of bounded boundary rotation. Coefficient estimates, an inclusion result, arclength problem, and some other properties of these classes are studied.

1992 ◽  
Vol 15 (2) ◽  
pp. 279-289 ◽  
Author(s):  
Khalida Inayat Noor

The classesTk(ρ),0≤ρ<1,k≥2, of analytic functions, using the classVk(ρ)of functions of bounded boundary rotation, are defined and it is shown that the functions in these classes are close-to-convex of higher order. Covering theorem, arc-length result and some radii problems are solved. We also discuss some properties of the classVk(ρ)including distortion and coefficient results.


1969 ◽  
Vol 16 (4) ◽  
pp. 339-347 ◽  
Author(s):  
D. A. Brannan

Let Vk denote the class of functionswhich map conformally onto an image domain ƒ(U) of boundary rotation at most kπ (see (7) for the definition and basic properties of the class kπ). In this note we discuss the valency of functions in Vk, and also their Maclaurin coefficients.In (8) it was shown that functions in Vk are close-to-convex in . Here we show that Vk is a subclass of the class K(α) of close-to-convex functions of order α (10) for , and we give an upper bound for the valency of functions in Vk for K>4.


2018 ◽  
Vol 16 (1) ◽  
pp. 1161-1169
Author(s):  
Varadharajan Radhika ◽  
Jay M. Jahangiri ◽  
Srikandan Sivasubramanian ◽  
Gangadharan Murugusundaramoorthy

AbstractWe consider the Toeplitz matrices whose elements are the coefficients of Bazilevič functions and obtain upper bounds for the first four determinants of these Toeplitz matrices. The results presented here are new and noble and the only prior compatible results are the recent publications by Thomas and Halim [1] for the classes of starlike and close-to-convex functions and Radhika et al. [2] for the class of functions with bounded boundary rotation.


2015 ◽  
Vol 267 ◽  
pp. 790-794
Author(s):  
Yaşar Polatog̃lu ◽  
Melike Aydog̃an ◽  
Yasemin Kahramaner

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