Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Two-Step Many-Objective Optimal Power Flow Based on Knee Point-Driven
  Evolutionary Algorithm
21
The categories of this paper are: adap-org
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
24
The categories of this paper are: dg-ga
17
The categories of this paper are: q-fin
1
The categories of this paper are: cs
4
The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc