Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Exterior algebra methods for the construction of rational surfaces in
  the projective fourspace
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
28
The categories of this paper are: alg-geom
6
The categories of this paper are: astro-ph
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg