Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: A classification theorem for static vacuum black holes. Part I: the
  study of the lapse
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
4
The categories of this paper are: cond-mat
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph