Computational Methods and Function Theory 4 (2004), No. 1, 151--158
Copyright Heldermann Verlag 2004
Michael Dorff
mdorff@math.byu.edu , Department of Mathematics, Brigham Young University, Provo, Utah, 84602, U.S.A.
Maria Nowak
nowakm@golem.umcs.lublin.pl , Department of Mathematics, Maria Curie-Sklodowska University, 20-031 Lublin, Poland.
Landau gave a lower estimate for the radius of a schlicht disk centered at the origin and contained in the image of the unit disk under a bounded holomorphic function f normalized by f(0)=f'(0)-1=1. Chen, Gauthier, and Hengartner established analogous versions for bounded harmonic functions. We improve upon their estimates.
Keywords: Landau Theorem, planar harmonic mappings.
MSC 2000: 30C99, 30C62.
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