Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Balanced algebraic unknotting, linking forms, and surfaces in three- and
  four-space
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg