Refinement of the coefficient problems for general subclass of m-fold symmetric bi-univalent functions

In this paper, a general subclass $${\mathcal {H}}_{{\Sigma }_m}^{h,p}(\lambda , \mu )$$ of m-fold symmetric bi-univalent function is introduced. Estimates on the coefficients $$|a_{m+1}|$$ and $$|a_{2m+1}|$$ for functions in the subclass $${\mathcal {H}}_{{\Sigma }_m}^{h,p}(\lambda ,\mu )$$ are obtained. The results presented in this paper would generalize and improve some recent works of several earlier authors.