Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Relaying Topological Interface States for Negative Refraction of Bulk
  Waves
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
18
The categories of this paper are: econ