MEROMOR0PHIC UNIVALENT HARMONIC FUNCTIONS WITH NEGATIVE COEFFICIENTS

  • Published : 1999.11.01

Abstract

The purpose of this paper is to give sufficient coefficient conditions for a class of univalent harmonic functions that map each $$\mid$z$\mid$$ = r >1 onto a curve that bounds a domain that is starlike with respect to origin. Furthermore, it is shown that these conditions are also necessary when the coefficients are negative. Extreme points for these classes are also determined. Finally, comparable results are given for the convex analgo.

Keywords

References

  1. Ann. Acad. Sci. Fenn. Ser Al Math. v.9 Harmonic Univalent Functions J. Clunie;T. Sheill-Small
  2. Univalent Functions P. L. Duren
  3. Trans. Amer. Math. Soc. v.299 W. Hengartner;G. Schober
  4. J. Korean Math. Soc. v.32 no.4 Planar harmonic mappings and curvature estimates S. H. Jun
  5. J. London Math. Soc. v.42 no.2 Constants for planar harmonic mappings T. Sheil-Small
  6. J. Math. Anal. Appl. v.220 Harmonic univalent functions negative coefficients H. Silverman