Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On periodic boundary value problem for the Sturm-Liouville operator   We consider the Sturm-Liouville operator Lu=u''-q(x)u with periodic or
antiperiodic boundary conditions. It is shown that depending of Fourier
coefficients of the potential q(x) the system of root functions may have or may
not have the basis property.

37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
6
The categories of this paper are: astro-ph
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
21
The categories of this paper are: adap-org
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex