Izvestiya of Saratov University.

Mathematics. Mechanics. Informatics

ISSN 1816-9791 (Print)

ISSN 2541-9005 (Online)

two-fold expansion in the eigenfunctions

Expansion in Eigenfunctions of Quadratic Strongly Irregular Pencils of Differential Operators of the Second Order

Expansion in Root Functions of Strongly Irregular Pencil of Differential Operators of the Second Order with Multiple Characteristics