Univalent functions defined by Ruscheweyh derivatives

Univalent Functions Defined by Ruscheweyh Derivatives

We study some radii problems concerning the integral operator z F(z)y+l uY-I f(u) du zy o for certain classes, namely K and M (a), of univalent functions defined by Ruscheweyh n n derivatives. Infact, we obtain the converse of Ruscheweyh’s result and improve a result of Goel and Sohi for complex by a different technique. The results are sharp.

Properties on a subclass of univalent functions defined by using a multiplier transformation and Ruscheweyh derivative

In this paper we have introduced and studied the subclass RI(d, α, β) of univalent functions defined by the linear operator RI n,λ,lf(z) defined by using the Ruscheweyh derivative Rf(z) and multiplier transformation I (n, λ, l) f(z), as RI n,λ,l : A → A, RI γ n,λ,lf(z) = (1 − γ)R f(z) + γI (n, λ, l) f(z), z ∈ U, where An = {f ∈ H(U) : f(z) = z+ an+1z + . . . , z ∈ U} is the class of normalized ...

Univalent Functions with Univalent Derivatives. Ii

Faber polynomial coefficient estimates for bi-univalent functions defined by subordinations

A function is said to be bi-univalent on the open unit disk D if both the function and its inverse are univalent in D. Not much is known about the behavior of the classes of bi-univalent functions let alone about their coefficients. In this paper we use the Faber polynomial expansions to find coefficient estimates for four well-known classes of bi-univalent functions which are defined by subord...

On univalent functions defined by a generalized Sălăgean operator