Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Comment on "Black Holes are Neither Particle Accelerators Nor Dark
  Matter Probes"   The Banados-Silk-West effect consists in the possibility to get infinite
energy in the centre of mass frame of two particles colliding near the black
hole horizon. According to S. T. McWilliams, Phys. Rev. Lett. 110 (2013)
011102, the energy at infinity of the outcome vanishes because of infinite
redshift when the point of collision approaches the horizon. I show that this
is not so.

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The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol