Abstract
We connect the pre-Schwarzian norm of logharmonic mappings to the pre-Schwarzian norm of an analytic function and establish some necessary and sufficient conditions under which locally univalent logharmonic mappings have a finite pre-Schwarzian norm. We also obtain a necessary and sufficient condition for a logharmonic function to be Bloch. Furthermore, we obtain the pre-Schwarzian norm and growth theorem for logharmonic Bloch mappings and their analytic and co-analytic parts.
Similar content being viewed by others
Data Availability
Data sharing not applicable to this article as no data sets were generated or analyzed during the current study.
References
Abdulhadi, Z., Bshouty, D.: Univalent functions in \(H{\overline{H}}\). Tran. Amer. Math. Soc. 305(2), 841–849 (1988)
Abdulhadi, Z., Ali, R.M.: Univalent logharmonic mappings in the plane. Abstr. Appl. Anal. 2012 (2012). Art. ID 721943, 32 pp
Anderson, J., Clunie, J., Pommerenke, Ch.: On Bloch functions and normal functions, pp. 12–37. Walter de Gruyter, Berlin/New York Berlin, New York (1974)
Becker, J.: Löwnersche Differentialgleichung und quasikonform fortsetzbare schlichte Funktionen. J. Reine Angew. Math. 255, 23–43 (1972)
Becker, Pommerenke: Schlichtheitskriterien und Jordangebiete. J. Reine Angew. Math. 354, 74–94 (1984)
Bravo, V., Hernández, R., Ponnusamy, S., Venegas, O.: Pre-Schwarzian and Schwarzian derivatives of Logharmonic mapppings. Monatsh. Math. 1–22 (2022)
Chuaqui, M., Duren, P., Osgood, B.: The Schwarzian derivative for harmonic mappings. J. Anal. Math. 91(1), 329–351 (2003)
Duren, P.L.: Univalent Functions. Springer-Verlag, Berlin (1983)
Graf, SYu.: On the schwarzian norm of harmonic mappings. Probl. Anal. Issues Anal. 5(2), 20–32 (2016)
Hernández, R., Martín, M.J.: Quasi-conformal extensions of harmonic mappings in the plane. Ann. Acad. Sci. Fenn. Ser. A. I Math. 38, 617–630 (2013)
Hernández, R., Martín, M.J.: Pre-Schwarzian and Schwarzian derivatives of harmonic mappings. J. Geomet. Anal. 25(1), 64–91 (2015)
Huusko, J.M., Martín, M.J.: Criteria for bounded valence of harmonic mappings. Comput. Methods Funct. Theory 17(4), 603–612 (2017)
Kraus, W.: Uber den Zusammenhang eigner Characterstiken eines einfach zusammenhangenden Bereiches mit der Kreisabbildung. Mitt. Math. Sem. Giessen 21, 1–28 (1932)
Liu, Z., Ponnusamy, S.: Some properties of univalent log-harmonic mappings. Filomat 32(15), 5275–5288 (2018)
Liu, G., Ponnusamy, S.: Uniformly locally univalent harmonic mappings associated with the pre-Schwarzian norm. Indagationes Mathematicae 29(2), 752–778 (2018)
Mao, Z., Ponnusamy, S., Wang, X.: Schwarzian derivative and Landau’s theorem for logharmonic mappings. Complex Var. Elliptic Equ. 58(8), 1093–1107 (2013)
Nehari, Z.: The Schwarzian derivative and schlicht functions. Bull. Amer. Math. Soc. 55(6), 545–551 (1949)
Pommerenke, Ch.: On Bloch functions. J. London Math. Soc. 2(2), 689–695 (1970)
Yamashita, S.: Almost locally univalent functions. Monatsh. Math. 81, 235–240 (1976)
Acknowledgements
The authors thank the referee for the constructive comments which helped to improve the presentation of the paper. The second named author thanks the Department Of Science and Technology, Ministry Of Science and Technology, Government Of India, for the financial support through DST-INSPIRE Fellowship (No. DST/INSPIRE Fellowship/2018/IF180967).
Author information
Authors and Affiliations
Contributions
All authors contributed equally to the investigation of the problem and the order of the authors is given alphabetically according to their surname. All authors read and approved the final manuscript.
Corresponding author
Ethics declarations
Conflict of interest
The authors declare that they have no conflict of interest.
Additional information
Communicated by See Keong Lee.
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Ali, M.F., Pandit, S. On the Pre-Schwarzian Norm of Certain Logharmonic Mappings. Bull. Malays. Math. Sci. Soc. 47, 67 (2024). https://doi.org/10.1007/s40840-024-01668-6
Received:
Revised:
Accepted:
Published:
DOI: https://doi.org/10.1007/s40840-024-01668-6
Keywords
- Analytic function
- Harmonic function
- Logharmonic function
- Logharmonic Bloch function
- Convex function
- Pre-Schwarzian norm