Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Comparing $f(R)$ modified gravity and noncommutative geometry in the
  context of dark matter and traversable wormholes: a survey   Noncommutative geometry, as conceptualized by Nicolini, Smailagic, and
Spallucci, may be viewed as a slight modification of Einstein's theory. The
same can be said for $f(R)$ modified gravity for an appropriate choice of the
function $f(R)$. Since such an $f(R)$ could be determined from the
noncommutative-geometry background, these gravitational theories make very
similar predictions in the discussion of (a) dark matter and (b) traversable
wormholes; they can therefore be taken as equally viable models.

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The categories of this paper are: cond-mat
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The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
22
The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
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The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
6
The categories of this paper are: astro-ph