Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Symmetries and infinitesimal symmetries of singular differential
  equations   The aim of this paper is to study symmetries of linearly singular
differential equations, namely, equations that can not be written in normal
form because the derivatives are multiplied by a singular linear operator.
  The concept of geometric symmetry of a linearly singular differential
equation is introduced as a transformation that preserves the geometric data
that define the problem. It is proved that such symmetries are essentially
equivalent to dynamic symmetries, that is, transformations mapping solutions
into solutions. Similar results are given for infinitesimal symmetries.
  To study the invariance of several objects under the flows of vector fields,
a careful study of infinitesimal variations is performed, with a special
emphasis on infinitesimal vector bundle automorphisms.

29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
19
The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
20
The categories of this paper are: acc-phys
32
The categories of this paper are: atom-ph
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol