Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Can gravitational collapse and black-hole evaporation be a unitary
  process after all?   This paper shows a way of how one may resolve the non-unitarity problem in
black-hole physics without modifications of the basic principles of local
quantum field theory.

21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat