Abstract
Quantitative estimates are obtained for the (finite) valence of functions analytic in the unit disk with Schwarzian derivative that is bounded or of slow growth. A harmonic mapping is shown to be uniformly locally univalent with respect to the hyperbolic metric if and only if it has finite Schwarzian norm, thus generalizing a result of B. Schwarz for analytic functions. A numerical bound is obtained for the Schwarzian norms of univalent harmonic mappings.
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References
G. Birkhoff and G.-C. Rota, Ordinary Differential Equations, 4th Edition, Wiley, New York, 1989.
M. Chuaqui, P. Duren and B. Osgood, The Schwarzian derivative for harmonic mappings, J. Analyse Math. 91 (2003), 329–351.
—, Univalence criteria for lifts of harmonic mappings to minimal surfaces, to appear in J. Geom. Analysis.
—, Schwarzian derivative criteria for valence of analytic and harmonic mappings, to appear in Math. Proc. Cambridge Philos. Soc.
M. Chuaqui and J. Gevirtz, Simple curves in ℝn and Ahlfors’ Schwarzian derivative, Proc. Amer. Math. Soc. 132 (2004), 223–230.
M. Chuaqui and R. Hernández, Univalent harmonic mappings and linearly connected domains, to appear in J. Math. Anal. Appl.
M. Chuaqui and B. Osgood, Sharp distortion theorems associated with the Schwarzian derivative, J. London Math. Soc. 48 (1993), 289–298.
P. L. Duren, Univalent Functions, Springer-Verlag, New York, 1983.
P. L. Duren, Harmonic Mappings in the Plane Cambridge University Press, Cambridge, U. K., 2004.
E. Kamke, Differentialgleichungen: Lösungsmethoden und Lösungen, Band 1: Gewöhnliche Differentialgleichungen, 3. Auflage, Becker & Erler, Leipzig, 1944; reprinted by Chelsea Publishing Co., New York, 1948.
W. Kraus, Über den Zusammenhang einiger Characteristiken eines einfach zusammenhängenden Bereiches mit der Kreisabbildung, Mitt. Math. Sem. Giessen 21 (1932), 1–28.
D. Minda, The Schwarzian derivative and univalence criteria, in: D. B. Shaffer (ed.), Topics in Complex Analysis, Contemporary Math. 38 (1985), 43–52.
Z. Nehari, The Schwarzian derivative and schlicht functions, Bull. Amer. Math. Soc. 55 (1949), 545–551.
Z. Nehari, Some criteria of univalence, Proc. Amer. Math. Soc. 5 (1954), 700–704.
Z. Nehari, A property of convex conformal maps, J. Analyse Math. 30 (1976), 390–393.
Z. Nehari, Univalence criteria depending on the Schwarzian derivative, Illinois J. Math. 23 (1979), 345–351.
V. V. Pokornyi, On some sufficient conditions for univalence, (in Russian) Dokl. Akad. Nauk SSSR 79 (1951), 743–746.
Ch. Pommerenke, Linear-invariante Familien analytischer Funktionen I, Math. Annalen 155 (1964), 108–154.
B. Schwarz, Complex nonoscillation theorems and criteria of univalence, Trans. Amer. Math. Soc. 80 (1955), 159–186.
T. Sheil-Small, Constants for planar harmonic mappings, J. London Math. Soc. 42 (1990), 237–248.
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Dedicated to Walter Hayman on the occasion of his 80th birthday
The authors are supported by Fondecyt Grant # 1030589.
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Chuaqui, M., Duren, P. & Osgood, B. Schwarzian Derivatives and Uniform Local Univalence. Comput. Methods Funct. Theory 8, 21–34 (2008). https://doi.org/10.1007/BF03321667
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DOI: https://doi.org/10.1007/BF03321667
Keywords
- Analytic function
- valence
- harmonic mapping
- Schwarzian derivative
- uniform local univalence
- Schwarzian norm
- minimal surface
- harmonic lift