Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The space-time models with dust matter that admit separation of
  variables in Hamilton-Jacobi equations of a test particle   The characteristics of dust matter in space-time models, admitting the
existence of privilege coordinate systems are given, where the single-particle
Hamilton-Jacobi equation can be integrated by the method of complete separation
of variables. The resulting functional form of the 4-velocity field and energy
density of matter for all types of spaces under consideration is presented.

20
The categories of this paper are: acc-phys
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The categories of this paper are: eess
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
4
The categories of this paper are: cond-mat
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph