On the Minimality of a Part of Eigen- And Associated Vectors for a Class of Third-Order Quasi-Elliptic Ope

Abstract

In the paper, we derive sufficient conditions on the coefficients of a thirdorder quasi-elliptic operator pencil, ensuring the minimality of its system of eigen- and associated vectors corresponding to eigenvalues from the left half-plane. Additionally, we prove a theorem on the minimality of decreasing elementary solutions to a homogeneous equation in a Sobolev-type space.