Open access
Aug 2026
The Sharp Bound for the Fourth Hankel Determinant over Functions with Positive Real-Part Derivative
Let D be the open unit disk and let R denote the class of normalized analytic functions whose derivatives have positive real part. We determine the sharp upper bound 8/125 for the absolute value of the fourth Hankel determinant H(4,1). The determinant is represented as an integer polynomial in the first six Carathéodor...
Musthafa Ibrahim, Zainab H. Mahmood, Reem O. Rasheed et al.
· Basrah journal of science · 0 citations