Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Regularity properties of singular degenerate abstract differential
  equations and applications   Singular degenerate differential operator equations are studied. The uniform
separability of boundary value problems for degenerate elliptic equation and
optimal regularity properties of Cauchy problem for degenerate parabolic
equation are obtained. These problems have a numeros applications which occur
in fluid mechanics, environmental engineering and atmospheric dispersion of
pollutants.

6
The categories of this paper are: astro-ph
1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con