Abstract
Avkhadiev's classes consist of holomorphic functions with a two-sided restriction on the module of the derivative. We study these classes in domains different from the unit disk. For the images of the domains under the mappings of Avkhadiev's classes, we find conditions providing the uniqueness of critical point of the conformal radius. We use an analogue of the concept that Lehto applied to study univalence of functions satisfying the conditions of Nehari type in domains conformally equivalent to a disk.
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REFERENCES
Avkhadiev, F.G., Aksent'ev, L.A., Elizarov, A.M., Kazantsev, A.V. “Geometric function theory methods in the unique solvability analysis of the boundary-value problems with free parameters” (in: Proc. IV Int. Conf. 'Lavrentiev readings in mathematics, mechanics and physics', Kazan, July 3–7, 1995, p. 21 (Novosibirsk, 1995)).
Lavrentiev, M.A., Shabat, B.V. Methods of the Function Theory of a Complex Variable (Nauka, Moscow, 1973) [in Russian].
Gakhov, F.D. Boundary Value Problems (Dover Publ., Inc, New York, 1990).
Tumashev, G.G., Nuzhin, M.T. Inverse Boundary Value Problems and Appliations (Kazan Univ., Kazan, 1965) [in Russian].
Friedman, A. Variational Principles and Free-Boundary Problems (John Wiley & Sons, 1982).
Avkhadiev, F.G. An inverse boundary value problem for a function with singularities, Trudy Sem. Kraev. Zadacham, Kazan University 21, 5–19 (1984).
Avkhadiev, F.G., Shabalina, S.B. “Zeros of coefficients of transformations and conditions for the solvability of inverse boundary value problems”, Russian Math. (Iz. VUZ) 38 (8), 1–9 (1994).
Avkhadiev, F.G., Aksent'ev, L.A., Elizarov, A.M. “Sufficient conditions for the finite-valence of analytic functions, and their applications”, J. Soviet Math. 49 (1), 715–799 (1990).
Nehari, Z. “The Schwarzian derivative and schlicht functions”, Bull. Amer. Math. Soc. 55(6), 545–551 (1949).
Avkhadiev, F.G. Conformal Mappings and Boundary Value Problems (Kazan Univ., Kazan, 2019) [in Russian].
Gehring, F.W., Pommerenke, Ch. “On the Nehari univalence criterion and quasicircles”, Comment. Math. Helv. 59, 226–242 (1984).
Aksent'ev, L.A., Kazantsev, A.V. “A new property of the Nehari class and its application”, Soviet Math. (Iz. VUZ) 33 (8), 94–99 (1989).
Haegi, H.R. “Extremalprobleme und Ungleichungen konformer Gebietsgröß en”, Compositio Math. 8(2), 81–111 (1950).
Kazantsev, A.V. “Gakhov set in the Hornich space under the Bloch restriction on pre-Schwarzians”, Uchenye Zapiski Kazanskogo Universiteta. Seriya Fiziko-Matematicheskie Nauki 155 (2), 65–82 (2013).
Kazantsev, A.V. “On the exit out of the Gakhov set controlled by the subordination conditions”, Uchenye Zapiski Kazanskogo Universiteta. Seriya Fiziko-Matematicheskie Nauki 156 (1), 31–43 (2014).
Ruscheweyh, St., Wirths, K.-J. “On extreme Bloch functions with prescribed critical points”, Math. Z. 180, 91–106 (1982).
Aksent'ev, L.A. “The connection of the exterior inverse boundary value problem with the inner radius of the domain”, Soviet Math. (Iz. VUZ) 28 (2), 1–13 (1984).
Lehto, O. “Domain constants associated with Schwarzian derivative”, Comment. Math. Helv. 52(4), 603–610 (1977).
Lehto, O. “Univalent functions, Schwarzian derivatives and quasiconformal mappings”, L'Enseignement Math. 24(3Ц4), 203–214 (1978).
Kazantsev, A.V. “On the exit from the Gakhov set along the family of Avkhadiev's classes”, Uchenye Zapiski Kazanskogo Universiteta. Seriya Fiziko-Matematicheskie Nauki 159 (3), 318–326 (2017) .
Goluzin, G.M. Geometric Theory of Functions of a Complex Variable (AMS, Transl. of Math. Monographs, Vol.26, 1969).
Bakelman, I.Ya., Verner, A.L., Kantor, B.E. Introduction to Differential Geometry “in General” (Nauka, Moscow, 1973).
Kazantsev, A.V.“Bifurcations and new uniqueness criteria for the critical points of hyperbolic derivatives”, Uchenye Zapiski Kazanskogo Universiteta. Seriya Fiziko-Matematicheskie Nauki 153 (1), 180–194 (2011).
Kazantsev, A.V. Four Etudes on the Gakhov Theme (Mariiskii Univ., Yoshkar-Ola, 2012).
ACKNOWLEDGMENTS
The authors express their sincere gratitude to the anonymous referee for remarks which essentially improve the text of the paper.
Funding
The work is fulfilled under the financial support of the Russian Foundation for Basic Research and the Government of the Republic of Tatarstan, project no. 18-41-160017.
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Russian Text © The Author(s), 2021, published in Izvestiya Vysshikh Uchebnykh Zavedenii. Matematika, 2021, No. 3, pp. 47–55.
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Kazantsev, A.V., Kinder, M.I. Avkhadiev–Lehto Type Constants in the Study of the Gakhov Class. Russ Math. 65, 43–50 (2021). https://doi.org/10.3103/S1066369X2103004X
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DOI: https://doi.org/10.3103/S1066369X2103004X