Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: f(R,T) Cosmological Models in Phase Space   We investigate cosmological solutions of f(R,T) modified theories of gravity
for perfect fluid in spatially FLRW metric through phase space analysis, where
R is Ricci scalar and T denotes the trace of energy-momentum tensor of matter
content. We explore and analyze three general theories with Lagrangians of
minimal $g(R)+h(T)$, pure non--minimal g(R)h(T) and non-minimal $g(R)(1+h(T))$
couplings through dynamical systems approach. We introduce a few variables and
dimensionless parameters to simplify the equations in more concise forms. The
conservation of energy-momentum tensor leads to a constraint equation that, in
the minimal gravity, confines functionality of h(T) to a particular form,
hence, relates the dynamical variables. In this case, acceptable cosmological
solutions that contain a long enough matter dominated era followed by a
late-time accelerated expansion are found. To support theoretical results, we
also obtain numerical solutions for a few functions of g(R), and results of the
corresponding models confirm the predictions. We classify solutions into six
classes which demonstrate more acceptable solutions and there is more freedom
to have the matter dominated era than in the f(R) gravity. In particular, there
is a new fixed point which can represent late-time acceleration. We draw
different diagrams of the matter densities (consistent with the present
values), the related scale factors and effective equation of state. The
corresponding diagrams of parameters illustrate that there is a saddle
acceleration era which is a middle era before final stable acceleration de
Sitter era for some models. All presented diagrams determine radiation, matter
and late-time acceleration eras very well.

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The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
8
The categories of this paper are: hep-ex
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph