Sharp bounds of Fekete-Szegő functional for quasi-subordination class

In the present paper, we introduce a certain subclass 𝒦_q(λ, γ, h) of analytic functions by means of a quasi-subordination. Sharp bounds of the Fekete-Szegő functional for functions belonging to the class 𝒦_q(λ, γ, h) are obtained. The results presented in the paper give improved versions for the certain subclasses involving the quasi-subordination and majorization.