MATHEMATICS
On one method for constructing solutions to the homogeneous schwarz problem
V. G. Nikolaev Yaroslav-the-Wise Novgorod State University
Abstract:
The paper considers the homogeneous Schwarz problem for Douglis analytic or
$J$-analytic functions. The 2-2-matrix
$J$ has eigenvalues
$\lambda$,
$\mu$, lying above the real axis. The eigenvalues can be either distinct or multiples. In the second section of the paper there are given the problem statement and definitions of
$J$-analytic and
$\lambda$-holomorphic functions. At the beginning of the third section Lemma 3.1 is proved, establishing some relation between real and holomorphic functions. Then is constructed a special operator basis
$J$. For matrices with multiple eigenvalue this basis coincides with the Jordan basis of the matrix
$J$. Then with the help of this basis and Lemma 3.1 is constructed
$J$-analytic function
$\phi(z)$ in the form of a quadratic vector polynomial of some special form. If the eigenvalues
$\lambda$,
$\mu$ of the matrix
$J$ are fixed, then the function
$\phi(z)$ depends on the elements of the first column of the matrix
$J$ as $parameters. These parameters are chosen so that the real part of the function $\phi(z)
$ has the form $(P; 0
$), where $P = P(x, y)
$ is a positively defined quadratic form. All $J$-analytic functions are defined with the accuracy of the additive vector constant Therefore, the function $\phi(z) - (1, 0)$ will be the required solution to the homogeneous Schwarz problem in the ellipse &\Gamma; : P(x, y) = 1$. Then the matrix
$J$ is reconstructed by the known elements of the first column and the eigenvalues
$\lambda$,
$\mu$. The obtained result is formalized in the form of Theorem 3.1. At the end of the paper there are given six examples constructed according to the algorithm described above.
Keywords:
douglis analytic functions, lambda-Holomorphic functions, matrix eigenvalue, operator basis, ellipse. Received: 30.12.2023
Accepted: 30.12.2023
DOI:
10.52575/2687-0959-2023-55-4-305-312