Reem O. Rasheed

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...