Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the spectrum of second order differential operators with complex
  coefficients   The Weyl-Sims classification for a second-order ordinary differential
equation with general complex coefficients is investigated. Connections are
then established between the associated m-function and the spectral properties
of maximal-accretive realisations of the differential expression.

14
The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con