Mathematics (Sep 2020)

On the Difference of Coefficients of Starlike and Convex Functions

  • Young Jae Sim,
  • Derek K. Thomas

DOI
https://doi.org/10.3390/math8091521
Journal volume & issue
Vol. 8, no. 9
p. 1521

Abstract

Read online

Let f be analytic in the unit disk D={z∈C:|z|1}, and S be the subclass of normalized univalent functions given by f(z)=z+∑n=2∞anzn for z∈D. Let S*⊂S be the subset of starlike functions in D and C⊂S the subset of convex functions in D. We give sharp upper and lower bounds for |a3|−|a2| for some important subclasses of S* and C.

Keywords