Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On extended sign-changeable interactions in the dark sector   We extend the cosmological couplings proposed in Sun et al. and Wei, where
they suggested interactions with change of signs along the cosmological
evolution. Our extension liberates the changes of sign of the interaction from
the deceleration parameter and from the relation of energy densities of the
dark sector and considers the presence of non interactive matter. In three
cases we obtain the general solutions and the results obtained in models fitted
with Hubble's function and SNe Ia data, are analyzed regarding the problem of
the cosmological coincidence, the problem of the crisis of the cosmological age
and the magnitude of the energy density of dark energy at early universe. Also
we graphically study the range of variation of, the actual dark matter density
parameter, the effective equation of state of the dark energy and the redshift
of transition to the accelerated regimen, generated by variations at order
$1\sigma$ in the coupling parameters.

13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
14
The categories of this paper are: math-ph
17
The categories of this paper are: q-fin
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex