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A geometric criterion for decomposition and multivalence

Published online by Cambridge University Press:  24 October 2008

Y. Abu-Muhanna
Affiliation:
Department of Mathematical Sciences, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia
A. Lyzzaik
Affiliation:
Department of Mathematical Sciences, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia

Abstract

We give a quite general geometric criterion for a function analytic in the unit disc to be a polynomial of a univalent function, and hence a criterion for multivalence. We believe that this is the essence why multivalent close-to-convex functions enjoy the latter decomposition property. As another application, we study, as suggested by T. Sheil-Small ‘9’, the geometry of classes of analytic functions which arise from his recent investigation of multivalent harmonic mappings.

Type
Research Article
Copyright
Copyright © Cambridge Philosophical Society 1988

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References

REFERENCES

[1]Ahlfors, L. V. and Sario, L.. Riemann Surfaces (Princeton University Press, 1960).CrossRefGoogle Scholar
[2]Clunie, J. and Sheil-Small, T.. Harmonic univalent functions. Ann. Acad. Sci. Fenn. Ser A I Math. 9 (1984), 325.Google Scholar
[3]Farkas, H. M. and Kra, I.. Riemann Surfaces (Springer-Verlag, 1980).CrossRefGoogle Scholar
[4]Hummel, J. A.. Multivalent starlike functions. J. Analyse Math. 18 (1967), 133160.Google Scholar
[5]Livingston, A. E., p-valent close-to-convex functions. Trans. Amer. Math. Soc. 115 (1965), 161179.Google Scholar
[6]Lyzzaik, A.. Multivalent linearly accessible functions and close-to-convex functions. Proc. London Math. Soc. (3) 44 (1982), 178192.CrossRefGoogle Scholar
[7]Lyzzaik, A.. Multivalent functions of bounded boundary rotation and weakly close-to-convex functions. Proc. London Math. Soc. (3) 51 (1985), 478500.Google Scholar
[8]Pommerenke, C.. Univalent Functions (Vandenhoeck and Ruprecht, 1975).Google Scholar
[9]Sheil-Small, T.. On the Fourier series of a finitely described curve and a conjecture of H. S. Shapiro. Math. Proc. Cambridge Philos. Soc. 98 (1985), 513527.CrossRefGoogle Scholar
[10]Stoïlow, S.. Leçons sur les Principes Topologiques de la Theörie des Fonctions Analytiques, deuxième edition (Gauthier-Villars, 1956).Google Scholar
[11]Styer, D.. Close-to-convex multivalent functions with respect to weakly starlike functions. Trans. Amer. Math. Soc. 169 (1972), 105112.CrossRefGoogle Scholar