Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Cauchy-characteristic Evolution of Einstein-Klein-Gordon Systems: The
  Black Hole Regime
33
The categories of this paper are: plasm-ph
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
21
The categories of this paper are: adap-org
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
17
The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
14
The categories of this paper are: math-ph