A Criterion for Minimality of the Mixed Type Operators

This work is devoted to find a necessary and sufficient condition for the solvability of the overdetermined problem for the mixed-type equation with Cauchy data on the entire boundary. The proof of the main result is based on the representation of the boundary conditions of the Newton (volume) potential of the multidimensional Laplace equation, which was obtained in the work (Kal’menov and Suragan, Dokl Math 80(2):646–649, 2009).