Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On dummy variables of structure-preserving transformations   A method is given for obtaining equivalence subgroups of a family of
differential equations from the equivalence group of simpler equations of a
similar form, but in which the arbitrary functions specifying the family
element depend on fewer variables. Examples of applications to classical
equations are presented, some of which show how the method can actually be used
for a much easier determination of the equivalence group itself.

34
The categories of this paper are: chem-ph
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
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The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
1
The categories of this paper are: cs