Dirichlet problem for general A-harmonic equations in simply connected domains
DOI:
https://doi.org/10.15407/dopovidi2026.02.003Keywords:
Dirichlet problem, A-harmonic equation, simply connected domains, Beltrami equationsAbstract
The article is devoted to theorems on the existence, representation, and regularity of solutions to the Dirichlet problem with continuous data for general A-harmonic equation div A grad U = 0 in the real plane with matrix valued coefficients A. The equation is one of the main equations of the hydromechanics (fluid mechanics) in anisotropic and inhomogeneous media. Here we present a number of effective integral solvability criteria for this problem of the type of Calderon— Zygmund, Dini—Lavrentiev—Lehto, Orlicz, BMO, FMO and VMO in arbitrary bounded simple connected domains including all Jordan domains. These results are based on the theory of the so-called Beltrami equations with two characteristics in the complex plane and formulated in terms of the corresponding two complex parameters associated with A.
Downloads
References
Astala, K., Iwaniec, T. & Martin, G. (2009). Elliptic partial differential equations and quasiconformal mappings in the plane. Princeton Mathematical. Series 48. Princeton, NJ: Princeton University Press.
Heinonen, J., Kilpelainen, T. & Martio, O. (1993). Nonlinear potential theory of degenerate elliptic equations. Oxford: Oxford University Press.
Bojarski, B. V (2009). Generalized solutions of a system of differential equations of the first order and elliptic type with discontinuous coefficients. University of Jyväskylä. Department of Mathematics and Statistics, Report 118 (pp. 1-64). Jyväskylä: University Printing House.
Bojarski, B., Gutlyanskii, V. & Ryazanov, V. (2014). On existence and representation of solutions for general degenerate Beltrami equations. Complex Var. Elliptic Equ., 59, No. 1, pp. 67-75. https://doi.org/10.1080/17476933.2013.795955
Bojarski, B., Gutlyanskii, V. & Ryazanov, V. (2013). Dirichlet problem for the general Beltrami equation in Jordan domains. J. Math. Sci., 190, No. 4, pp. 525-538. https://doi.org/10.1007/s10958-013-1269-x
Bojarski, B., Gutlyanskii, V. & Ryazanov, V. (2012). On the Dirichlet problem for general degenerate Beltrami equations. Bull. Soc. Sci. Lett. Lodz, Ser. Rech. Deform., 62, No. 2, pp. 29-43.
Bojarski, B., Gutlyanskii, V. & Ryazanov, V. (2011). On integral conditions for the general Beltrami equations. Complex Anal. Oper. Theory, 5, No. 3, pp. 835-845. https://doi.org/10.1007/s11785-010-0088-z
Bojarski, B., Gutlyanskii, V. & Ryazanov, V. (2009). On the Beltrami equations with two characteristics. Complex Var. Elliptic Equ., 54, No. 10, pp. 935-950. https://doi.org/10.1080/17476930903030069
Gulyanskii, V., Ryazanov, V., Salimov, R. & Sevost’yanov, E. (2025). Dirichlet problem for general Beltrami equations in simply connected domains. Ukr. Math. Bull., 22, No. 4, pp. 477-498.
Bojarski, B., Gutlyanskii, V., Martio, O. & Ryazanov, V. (2013). Infinitesimal geometry of quasiconformal and bi-Lipschitz mappings in the plane. EMS Tracts in Mathematics, Vol. 19. Zürich: European Mathematical Society. https://doi.org/10.4171/122
Gutlyanskii, V., Ryazanov, V., Srebro, U. & Yakubov, E. (2012). The Beltrami equation: A geometric approach. Developments in Mathematics, Vol. 26. Berlin: Springer. https://doi.org/10.1007/978-1-4614-3191-6
Martio, O., Ryazanov, V., Srebro, U. & Yakubov, E. (2009). Moduli in modern mapping theory. Springer Monographs in Mathematics. New York: Springer. https://doi.org/10.1007/978-0-387-85588-2
Hencl S. & Koskela P. (2014). Lectures on mappings of finite distortion. Lecture Notes in Mathematics, Vol. 2096. Cham: Springer. https://doi.org/10.1007/978-3-319-03173-6
Gutlyanskii, V., Ryazanov, V., Sevost'yanov, E. & Yakubov, E. (2022). BMO and Dirichlet problem for degenerate Beltrami equation. J. Math. Sci., 268, No. 2, pp. 157-177. https://doi.org/10.1007/s10958-022-06189-w
Gutlyanskii, V. Ya., Ryazanov, V. I., Sevost’yanov, E. A. & Yakubov, E. (2023). On the Dirichlet problem for A-harmonic functions. Dopov. Nac. akad. nauk Ukr., No. 4, pp. 11-19. https://doi.org/10.15407/dopovidi2023.04.011
Ransford, Th. (1995). Potential theory in the complex plane. London Mathematical Society Student Texts, Vol. 28. Cambridge: Cambridge University Press. https://doi.org/10.1017/CBO9780511623776
John, F. & Nirenberg, L. (1961). On functions of bounded mean oscillation. Comm. Pure Appl. Math., 14, pp. 415-426. https://doi.org/10.1002/cpa.3160140317
Reimann, H.M. & Rychener, T. (1975). Funktionen beschränkter mittlerer oszillation. Lecture Notes in Mathematics, Vol. 487. Berlin: Springer. https://doi.org/10.1007/BFb0081825
Sarason, D. (1975). Functions of vanishing mean oscillation. Trans. Amer. Math. Soc., 207, pp. 391-405. https://doi.org/10.1090/S0002-9947-1975-0377518-3
Brezis, H. & Nirenberg, L. (1995). Degree theory and BMO; part I: Compact manifolds without boundaries. Selecta Math., New Ser., 1, No. 2, pp.197-263. https://doi.org/10.1007/BF01671566
Ignat’ev, A. A. & Ryazanov, V. I. (2005). Finite mean oscillation in the mapping theory. Ukr. Math. Bull., 2, No. 3, pp. 403-424.
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2026 Reports of the National Academy of Sciences of Ukraine

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

