Notes on certain class of analytic functions with negative coefficients (Q583426)

Let \(n\in {\mathbb{N}}\) and \((B_ k)_{k\geq n+1}^ a \)sequence of positive numbers. The authors deal with the extreme points of the class \(A(n,B_ k)\) of functions \(f(z)=z-\sum^{\infty}_{k=n+1}| a_ k| z^ k\) analytic in the unit disc such that \(\sum^{\infty}_{k=n+1}B_ k| a_ k| \leq 1\) and the support points of the said class under the additional assumption \(B_ k\geq k\) for \(k>n+1\).