# Non-Uniqueness of Solutions to Boundary Value Problems with Wentzell Condition

N.S. Goncharov, S.A. Zagrebina, G.A. SviridyukRecently, in the mathematical literature, the Wentzel boundary condition is considered from two points of view. In the first case, let us call it classical one, this condition is an equation containing a linear combination of the values of the function and its derivatives on the boundary of the domain. Moreover, the function itself also satisfies the equation with an elliptic operator defined in the domain. In the second case, which we call neoclassical one, the Wentzel condition is an equation with the Laplace - Beltrami operator defined on the boundary of the domain understood as a smooth compact Riemannian manifold without boundary, and the external action is represented by the normal derivative of a function defined in the domain. The paper shows the non-uniqueness of solutions to boundary value problems with the Wentzel condition in the neoclassical sense both for the equation with the Laplacian and for the equation with the Bilaplacian given in the domain.Full text

- Keywords
- Wentzell condition.
- References
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