Coefficient estimates for new subclasses of Ma-Minda bi-univalent functions

In this paper, we introduce and investigate two new subclasses H (, ) and M (, , ) of Ma-Minda bi-univalent functions defined by using subordination in the open unit disk D = {z C : |z| < 1}. For functions belonging to these new subclasses, we obtain estimates for the initial coefficients |a 2 | and |a 3 |. The results presented in this paper would generalize those in related works of several earlier authors.