Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: A Sharp-Interface Active Penalty Method for the Incompressible
  Navier-Stokes Equations
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con