In this paper we consider the class of functions with negative coefficients denned by differential integral operators. Among others the necessary and sufficient condition for a function f to be in the studied class is presented.
In the present paper the second order differential subordination (1 - alpha)f(z/z + alphaf'{z) + betazf(z) [...] 1 + Mz \z is an element of U) is investigated. The best dominant of subordination (1) is founded. Connections between subordination (1) and subordination of f(z)/z, f'{z) are given. Further the convexity of the function / satisfying the subordination (1) for special choice of parameters a, alpha, beta and M are derived.
3
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
In the present paper, the authors investigate the univalence of the functions f, analytic in -E, f(O) = 0, f'(0) = 1 and which satisfy Re [(1 - alfa)f'(z) + alfa (1+ zf''(z): f'(z)] >beta, z is an element of E, where alfa > 0 and 0 < beta < 1. The univalence of such functions has already been established in the case when alfa < 0 and beta = 0 by H. S. Al-Amiri and M. 0. Reade in 1975.
In the present paper, the authors introduce two new subclasses S(sup k) (sub sc) (γ, α β) of close-to-convex functions and C(sup k) (sub sc) (γ, α β) of quasi-convex functions with respect to 2k-symmetric conjugate points. The inclusion and subordination relationships, convolution conditions for these classes are provided. The coefficient inequalities, integral representations and sufficient conditions for functions belonging to these classes are also provided.
Let the function pa,b,s-so with a, b real, nonnegative numbers and s, so is an element of R, be a conform al mapping of the unit disk onto a hyperbolic domain. We establish the conditions udner which the differential subordination of the type p(z) +[...]zp'(z) -< pa,b,s-so(^) yields p -< pa,b,s- so(z) yields p [...] pa,b,s in U. Some applications of obtained results are given.
7
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
The object of the present paper is to derive various properties and char- acteristics of certain subclasses of p-valently analytic functions of order alpha in the open unit disc by using the techniques involving the Briot-Bouquet differential subordination.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.