Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the cosmological vacuum and dark energy   A degenerate fermionic vacuum population is suggested. Based on the abundance
of the dark energy density in the Universe the vacuum particle mass and number
density are estimated. The obtained mass is in reasonable agreement with
observations and predictions of the neutrino mass. Number densities are higher
than those of the relativistic relic neutrino component.

29
The categories of this paper are: funct-an
2
The categories of this paper are: math
7
The categories of this paper are: hep-th
4
The categories of this paper are: cond-mat
0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex