On a theorem of Haimo regarding concave mappings

Martin Chuaqui; Peter Duren; Brad Osgood

Annales UMCS, Mathematica (2011)

  • Volume: 65, Issue: 2, page 17-28
  • ISSN: 2083-7402

Abstract

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A relatively simple proof is given for Haimo's theorem that a meromorphic function with suitably controlled Schwarzian derivative is a concave mapping. More easily verified conditions are found to imply Haimo's criterion, which is now shown to be sharp. It is proved that Haimo's functions map the unit disk onto the outside of an asymptotically conformal Jordan curve, thus ruling out the presence of corners.

How to cite

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Martin Chuaqui, Peter Duren, and Brad Osgood. "On a theorem of Haimo regarding concave mappings." Annales UMCS, Mathematica 65.2 (2011): 17-28. <http://eudml.org/doc/268263>.

@article{MartinChuaqui2011,
abstract = {A relatively simple proof is given for Haimo's theorem that a meromorphic function with suitably controlled Schwarzian derivative is a concave mapping. More easily verified conditions are found to imply Haimo's criterion, which is now shown to be sharp. It is proved that Haimo's functions map the unit disk onto the outside of an asymptotically conformal Jordan curve, thus ruling out the presence of corners.},
author = {Martin Chuaqui, Peter Duren, Brad Osgood},
journal = {Annales UMCS, Mathematica},
keywords = {Concave mapping; Schwarzian derivative; Schwarzian norm; Haimo's theorem; univalence; Sturm comparison; asymptotically conformal curve; concave mapping},
language = {eng},
number = {2},
pages = {17-28},
title = {On a theorem of Haimo regarding concave mappings},
url = {http://eudml.org/doc/268263},
volume = {65},
year = {2011},
}

TY - JOUR
AU - Martin Chuaqui
AU - Peter Duren
AU - Brad Osgood
TI - On a theorem of Haimo regarding concave mappings
JO - Annales UMCS, Mathematica
PY - 2011
VL - 65
IS - 2
SP - 17
EP - 28
AB - A relatively simple proof is given for Haimo's theorem that a meromorphic function with suitably controlled Schwarzian derivative is a concave mapping. More easily verified conditions are found to imply Haimo's criterion, which is now shown to be sharp. It is proved that Haimo's functions map the unit disk onto the outside of an asymptotically conformal Jordan curve, thus ruling out the presence of corners.
LA - eng
KW - Concave mapping; Schwarzian derivative; Schwarzian norm; Haimo's theorem; univalence; Sturm comparison; asymptotically conformal curve; concave mapping
UR - http://eudml.org/doc/268263
ER -

References

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  2. Becker, J., Pommerenke, Ch., Über die quasikonforme Fortsetzung schlichter Funktionen, Math. Z. 161 (1978), 69-80. Zbl0393.30018
  3. Chuaqui, M., Duren, P. and Osgood, B., Schwarzian derivatives of convex mappings, Ann. Acad. Sci. Fenn. Math. 36 (2011), 449-460. Zbl1239.30003
  4. Chuaqui, M., Duren, P. and Osgood, B., Schwarzian derivative criteria for univalence of analytic and harmonic mappings, Math. Proc. Cambridge Philos. Soc. 143 (2007), 473-486. Zbl1134.30315
  5. Chuaqui, M., Duren, P. and Osgood, B., Concave conformal mappings and prevertices of Schwarz-Christoffel mappings, Proc. Amer. Math. Soc., to appear. Zbl1283.30048
  6. Chuaqui, M., Osgood, B., Sharp distortion theorems associated with the Schwarzian derivative, J. London Math. Soc. 48 (1993), 289-298. Zbl0792.30013
  7. Duren, P. L., Univalent Functions, Springer-Verlag, New York, 1983. 
  8. Duren, P., Schuster A., Bergman Spaces, American Mathematical Society, Providence, Rhode Island, 2004. 
  9. Gabriel, R. F., The Schwarzian derivative and convex functions, Proc. Amer. Math. Soc. 6 (1955), 58-66.[Crossref] Zbl0071.07002
  10. Haimo, D. T., A note on convex mappings, Proc. Amer. Math. Soc. 7 (1956), 423-428.[WoS][Crossref] Zbl0071.07003
  11. Nehari, Z., The Schwarzian derivative and schlicht functions, Bull. Amer. Math. Soc. 55 (1949), 545-551. Zbl0035.05104
  12. Nehari, Z., Some criteria of univalence, Proc. Amer. Math. Soc. 5 (1954), 700-704. Zbl0057.31102
  13. Nehari, Z., A property of convex conformal maps, J. Analyse Math. 30 (1976), 390-393. Zbl0334.30006
  14. Pommerenke, Ch., On univalent functions, Bloch functions and VMOA, Math. Ann. 236 (1978), 199-208. Zbl0385.30013

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