Abstract
For an inhomogeneous three-dimensional equation of mixed parabolic-hyperbolic type in a rectangular parallelepiped, the initial-boundary problem is studied. A criterion for the uniqueness of a solution is established. The solution is constructed as the sum of an orthogonal series. In substantiating the convergence of the series, the problem of small denominators of two natural arguments arose. Estimates are established for the separation from zero of the small denominators with the corresponding asymptotics. These estimates made it possible to justify the convergence of the constructed series in the class of regular solutions of this equation.
Similar content being viewed by others
REFERENCES
I. M. Gel’fand, ‘‘Some questions of analysis and differential equations,’’ Usp. Mat. Nauk 14 (3), 3–19 (1959).
Ya. S. Uflyand, ‘‘On the question of the propagation of oscillations in compound electric lines,’’ Eng. Phys. J. 7, 89–92 (1964).
Ya. S. Uflyand and I. T. Lozanovskaya, ‘‘On a Class of Problems of Mathematical Physics with a Mixed Spectrum of Eigenvalues,’’ Dokl. Akad. Nauk SSSR 164, 1005–1007 (1965).
T. D. Dzhuraev, A. Sopuev, and M. Mamazhanov, Boundary Value Problems for Parabolic-Hyperbolic Type Equations (Fan, Tashkent, 1986) [in Russian].
O. A. Ladyzhenskaya and L. Stupyalis, ‘‘On mixed-type equations,’’ Vestn. Leningr. Univ., Ser: Mat. Mekh. Astron. 19 (4), 38–46 (1965).
L. Stupyalis, ‘‘Initial-boundary value problems for equations of mixed type,’’ Proc. Steklov Inst. Math. 127, 135–170 (1975).
K. B. Sabitov, ‘‘Tricomi problem for a mixed parabolic–hyperbolic equation in a rectangular domain,’’ Math. Notes 86, 249–254 (2009).
K. B. Sabitov, Direct and Inverse Problems for Equations of Mixed Parabolic-Hyperbolic Type (Nauka, Moscow, 2016) [in Russian].
K. B. Sabitov, ‘‘Initial boundary and inverse problems for the inhomogeneous equation of a mixed parabolic-hyperbolic equation,’’ Math. Notes 102, 378–395 (2017).
S. N. Sidorov, ‘‘Nonlocal problem for a degenerate parabolic-hyperbolic equation,’’ Rep. Adyghe Int. Acad. Sci. 14 (3), 34–44 (2012).
K. B. Sabitov and S. N. Sidorov, ‘‘On a nonlocal problem for a degenerating parabolic-hyperbolic equation,’’ Differ. Equat. 50, 352–361 (2014).
S. N. Sidorov, ‘‘Nonlocal problems for an equation of mixed parabolic-hyperbolic type with power degeneration,’’ Russ. Math. (Iz. VUZ) 59 (12), 46–55 (2015).
K. B. Sabitov and S. N. Sidorov, ‘‘Initial boundary value problem for inhomogeneous degenerate equations of mixed parabolic-hyperbolic type,’’ Itogi Nauki Tekh., Ser.: Sovrem. Mat. Prilozh. Temat. Obz. 137, 26–60 (2017).
K. B. Sabitov and S. N. Sidorov, ‘‘Initial-boundary-value problem for inhomogeneous degenerate equations of mixed parabolic-hyperbolic type,’’ J. Math. Sci. 236, 603–640 (2019).
K. B. Sabitov and E. M. Safin, ‘‘The inverse problem for an equation of mixed parabolic-hyperbolic type,’’ Math. Notes 87, 880–889 (2010).
K. B. Sabitov and S. N. Sidorov, ‘‘Inverse problem for degenerate parabolic-hyperbolic equation with nonlocal boundary condition,’’ Russ. Math. (Iz. VUZ) 59 (1), 39–50 (2015).
S. N. Sidorov, ‘‘Inverse problems for a mixed parabolic-hyperbolic equation with a degenerate parabolic part,’’ Sib. Elektron. Mat. Izv. 16, 144–157 (2019).
S. N. Sidorov, ‘‘Inverse problems for a degenerate mixed parabolic-hyperbolic equation on finding time-depending factors in right hand sides,’’ Ufa Math. J. 11 (1), 75–89 (2019).
K. B. Sabitov, ‘‘Boundary-value problem for non-homogeneous mixed parabolic-hyperbolic type equation,’’ Lobachevskii J. Math. 38 (1), 137–147 (2017).
A. Ya. Khinchin, Continued Fractions (Dover, Mineola, New York, 1997).
A. A. Bukhshtab, Number Theory (Lan’, St. Petersburg, 2008) [in Russian].
V. A. Il’in, V. A. Sadovnichiy, and B. L. Sendov, Mathematical Analysis (Mosk. Gos. Univ., Moscow, 1987), Vol. 2 [in Russian].
Funding
The reported study was funded by Russian Foundation for Basic Research, project no. 19-31-60016.
Author information
Authors and Affiliations
Corresponding authors
Additional information
(Submitted by F. G. Avkhadiev)
Rights and permissions
About this article
Cite this article
Sabitov, K.B., Sidorov, S.N. Initial-Boundary Problem for a Three-Dimensional Inhomogeneous Equation of Parabolic-Hyperbolic Type. Lobachevskii J Math 41, 2257–2268 (2020). https://doi.org/10.1134/S1995080220110190
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S1995080220110190