Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: On Energy of the Friedman Universes in Conformally Flat Coordinates
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
16
The categories of this paper are: stat
22
The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
21
The categories of this paper are: adap-org
18
The categories of this paper are: econ
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
9
The categories of this paper are: nlin