Hankel determinant for certain new classes of analytic functions associated the activation functions

Heliyon. 2023 Oct 27;9(11):e21449. doi: 10.1016/j.heliyon.2023.e21449. eCollection 2023 Nov.

Abstract

In this article, we introduce two new classes of analytic functions Jtanh and JSG which are associated with the activation functions and defined by the ratio of analytic representations of convex and starlike functions. For functions in these classes, our primary goal is to determine the sharp upper bounds of second and third Hankel determinants.

Keywords: 30C45; 30C80; Activation functions; Coefficient bounds; Hankel determinant; Univalent mappings.