Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Load-Flow Solvability under Security Constraints in DC Distribution
  Networks
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
5
The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn
4
The categories of this paper are: cond-mat