Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Periodic Cosmological Evolutions of Equation of State for Dark Energy   We demonstrate two periodic or quasi-periodic generalizations of the
Chaplygin gas (CG) type models to explain the origins of dark energy as well as
dark matter by using the Weierstrass $\wp(t)$, $\sigma(t)$ and $\zeta(t)$
functions with two periods being infinite. If the universe can evolve
periodically, a non-singular universe can be realized. Furthermore, we examine
the cosmological evolution and nature of the equation of state (EoS) of dark
energy in the Friedmann-Lema\^{i}tre-Robertson-Walker cosmology. It is
explicitly illustrated that there exist three type models in which the universe
always stays in the non-phantom (quintessence) phase, whereas it always evolves
in the phantom phase, or the crossing of the phantom divide can be realized.
The scalar fields and the corresponding potentials are also analyzed for
different types of models.

25
The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
32
The categories of this paper are: atom-ph
6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
10
The categories of this paper are: q-bio