H. Rahmatan
Department of Mathematics, Payame Noor University, P.O. Box 19395-3697 Tehran, Iran.
[ 1 ] - The norm of pre-Schwarzian derivatives on bi-univalent functions of order $\alpha$
In the present investigation, we give the best estimates for the norm of the pre-Schwarzian derivative $ T_{f}(z)=\dfrac{f^{''}(z)}{f^{'}(z)} $ for bi-starlike functions and a new subclass of bi-univalent functions of order $ \alpha $, where $\Vert T_{f} \Vert= \sup_{|z|<1} (1-|z|^{2})|\dfrac{f^{''}(z)}{f^{'}(z)}|$.
Co-Authors