Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spatially homogeneous models of St\"ackel spacetimes of type (2.1)   All classes of spatially homogeneous space-time models are found that allow
the integration of the equations of motion of test particles and the eikonal
equation by the method of complete separation of variables according to type
(2.1). Four classes of model data are obtained. The resulting models can be
applied in any modified metric theories of gravity. Two of the above models
allow solutions of the Einstein equations with a cosmological constant and
radiation. For the models of a spatially homogeneous Universe with a
cosmological constant and radiation obtained in Einstein's theory of gravity,
the Hamilton-Jacobi equations of motion of the test particles and the eikonal
equation for radiation are integrated by the method of separation of variables.

10
The categories of this paper are: q-bio
1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
6
The categories of this paper are: astro-ph
3
The categories of this paper are: physics
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
24
The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat