Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Unfitted Nitsche's method for computing wave modes in topological
  materials
21
The categories of this paper are: adap-org
23
The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess
25
The categories of this paper are: patt-sol
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci