Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: On persistence of a Nicholson-type system with multiple delays and
  nonlinear harvesting
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph