Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Does black-hole evaporation imply that physics is non-unitary, and if
  so, what must the laws of physics look like? An Essay
12
The categories of this paper are: nucl-th
6
The categories of this paper are: astro-ph
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics
1
The categories of this paper are: cs
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
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg