Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the Physical Properties of Spherically Symmetric Self-Similar
  Solutions   In this paper, we are exploring some of the properties of the self-similar
solutions of the first kind. In particular, we shall discuss the kinematic
properties and also check the singularities of these solutions. We discuss
these properties both in co-moving and also in non co-moving (only in the
radial direction) coordinates. Some interesting features of these solutions
turn up.

1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
18
The categories of this paper are: econ
27
The categories of this paper are: comp-gas
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph