Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ideal gas sources for the Lemaitre-Tolman-Bondi metrics   New exact solutions emerge by replacing the dust source of the
Lem\^aitre-Tolman-Bondi metrics with a viscous fluid satisfying the monatomic
gas equation of state. The solutions have a consistent thermodynamical
interpretation. The most general transport equation of Extended Irreversible
Thermodynamics is satisfied, with phenomenological coefficients bearing a close
resemblance to those characterizing a non relativistic Maxwell-Bolzmann gas.

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The categories of this paper are: hep-ph
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
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The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn