Title of article :
The norm of preSchwarzian derivatives on biunivalent functions of order α
Author/Authors :
Rahmatan ، H. - Payame Noor University , Najafzadeh ، Sh. - Payame Noor University , Ebadian ، A. - Payame Noor University
Abstract :
In the present investigation, we give the best estimates for the norm of the pre-Schwarzian derivative Tf(z)=f′′(z)f′(z)Tf(z)=f″(z)f′(z) for bi-starlike functions and a new subclass of bi-univalent functions of order αα, where ∥Tf∥=sup|z| 1(1−|z|2)|f′′(z)f′(z)|‖Tf‖=sup|z| 1(1−|z|2)|f″(z)f′(z)|.
Keywords :
Bi , univalent functions , bi , starlike functions , subordination , pre , Schwarzian derivatives.
Journal title :
Bulletin of the Iranian Mathematical Society
Journal title :
Bulletin of the Iranian Mathematical Society
