Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Traversable Wormholes and Time Machines in non-minimally coupled
  curvature-matter $f(R)$ theories   We obtain traversable wormhole and time machine solutions of the field
equations of an alternative of gravity with non-minimally curvature-matter
coupling. Our solutions exhibit a non-trivial redshift function and allow for
matter that satisfy the dominant energy condition.

0
The categories of this paper are: hep-ph
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
19
The categories of this paper are: eess
14
The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas