Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Equivalence groupoids of classes of linear ordinary differential
  equations and their group classification   Admissible point transformations of classes of $r$th order linear ordinary
differential equations (in particular, the whole class of such equations and
its subclasses of equations in the rational form, the Laguerre-Forsyth form,
the first and second Arnold forms) are exhaustively described. Using these
results, the group classification of such equations is revisited within the
algebraic approach in three different ways.

14
The categories of this paper are: math-ph
6
The categories of this paper are: astro-ph
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
4
The categories of this paper are: cond-mat
29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
28
The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg