Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Recursion Relations for Tree-level Amplitudes in the SU(N) Non-linear
  Sigma Model
5
The categories of this paper are: gr-qc
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
1
The categories of this paper are: cs