DIRICHLET PROBLEM WHEN THE IMAGINARY UNIT IS THE DOUBLE ROOT OF A CHARACTERISTIC EQUATION
Keywords:
Dirichlet problem, defective numbers, nontrivial solutions of homogeneous Dirichlet problem, an improperly elliptic equationAbstract
The Dirichlet problem in a unit disc for a sixth order improperly elliptic equation is considered. At a certain arrangement of the roots of the characteristic equation, a new formula is obtained for determining the defective numbers. The case when is the double root of the characteristic equation is considered. The conditions for the solvability and solution of the homogeneous problem are determined in an explicit form.