Problems with Missing Tricomi Condition and Analog of Frankl Condition for One Class of Mixed Type Equations
Makulbay A. Mirsaburov M. Berdyshev A. Mirsaburova G.
June 2025Multidisciplinary Digital Publishing Institute (MDPI)
Mathematics
2025#13Issue 11
In this paper, for a mixed elliptic-hyperbolic type equation with various degeneration orders and singular coefficients, theorems of uniqueness and existence of the solution to the problem with a missing Tricomi condition on boundary characteristic and with an analog of Frankl condition on different parts of the cut boundary along the degeneration segment in the mixed domain are proved. On the degeneration line segment, a general conjugation condition is set, and on the boundary of the elliptic domain and degeneration segment, the Bitsadze–Samarskii condition is posed. The considered problem, based on integral representations of the solution to the Dirichlet problem (in elliptic part of the domain) and a modified Cauchy problem (in hyperbolic part of the domain), is reduced to solving a non-standard singular Tricomi integral equation with a non-Fredholm integral operator (featuring an isolated first-order singularity in the kernel) in non-characteristic part of the equation. Non-standard approaches are applied here in constructing the solution algorithm. Through successive applications of the theory of singular integral equations and then the Wiener–Hopf equation theory, the non-standard singular Tricomi integral equation is reduced to a Fredholm integral equation of the second kind, the unique solvability of which follows from the uniqueness theorem for the problem.
Bitsadze-Samarskii condition , Frankl condition analogue , missing Tricomi condition , mixed-type equation with various degeneration orders , Wiener–Hopf equation
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Department of Mathematics and Mathematical Modelling, Abai Kazakh National Pedagogical University, Almaty, 050010, Kazakhstan
Department of Mathematical Analysis, Termez State University, Termez, 190111, Uzbekistan
Department of General Mathematics, Tashkent State Pedagogical University, Tashkent, 100185, Uzbekistan
Department of Mathematics and Mathematical Modelling
Department of Mathematical Analysis
Department of General Mathematics
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