On certain classes of bi-univalent functions related to m -fold symmetry

In our present investigation, we introduce two new subclasses S Σ m ( α , λ , μ ) and S Σ m ( β , λ , μ ) of analytic and m -fold symmetric bi-univalent functions in the open unit disk E . Results concerning coefficient estimates for the functions of these classes are derived. Many interesting new and already existing corollaries are also presented.