Abstract
The Neumann problem for an equation with two perpendicular internal type-change lines in a rectangular domain is investigated. Uniqueness and existence theorems are proved by applying the spectral method. The separation of variables yields an eigenvalue problem for an ordinary differential equation. This problem is not self-adjoint, and the system of its eigenfunctions is not orthogonal. A corresponding biorthogonal system of functions is constructed and proved to be complete. The completeness result is used to prove a necessary and sufficient uniqueness condition for the problem under study. Its solution is constructed in the form of the sum of a biorthogonal series.
Similar content being viewed by others
References
F. I. Frankl, Izv. Akad. Nauk SSSR, Ser. Mat. 9, 387–422 (1945).
C. S. Morawetz, Michigan Math. J. 4 1, 5–14 (1957).
L. Bers, Mathematical Aspects of Subsonic and Transonic Gas Dynamics (New York Univ., New York, 1952; Inostrannaya Literatura, Moscow, 1961).
K. B. Sabitov and A. A. Akimov, Russ. Math. 45 10, 69–76 (2001).
E. I. Moiseev, Differ. Uravn. 35 8, 1094–1100 (1999).
K. B. Sabitov, Dokl. Math. 75 2, 193–196 (2007).
A. A. Gimaltdinova, Dokl. Math. 91 1, 41–46 (2015).
V. A. Il’in, Math. Notes 17 1, 53–58 (1975).
V. I. Arnol’d, Izv. Akad. Nauk SSSR, Ser. Mat. 25, 21–86 (1961).
I. S. Lomov, Differ. Uravn. 29 12, 2079–2089 (1993).
I. S. Lomov, Differ. Equations 47 3, 355–362 (2011).
M. V. Keldysh, Russ. Math. Surv. 26 4, 15–44 (1971).
Author information
Authors and Affiliations
Corresponding author
Additional information
Original Russian Text © A.A. Gimaltdinova, 2016, published in Doklady Akademii Nauk, 2016, Vol. 466, No. 1, pp. 7–11.
Rights and permissions
About this article
Cite this article
Gimaltdinova, A.A. Neumann problem for the Lavrent’ev–Bitsadze equation with two type-change lines in a rectangular domain. Dokl. Math. 93, 1–5 (2016). https://doi.org/10.1134/S1064562416010038
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S1064562416010038