New Results on Fourth-Hankel Determinant of a Certain Subclass of Analytic Functions

Abstract

    This paper studies the fourth Hankel determinaf for a subclass of analytic functions, denoted by N( , defined via athir-order differential subordination involving an exponential function. Sharp coefficient bounds for lanl, where  , are obtained, and an upper bound for the fourth Hankel determinant  is established, contributing to the theary of geometric function classes.