Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: An LQR-assisted Control Algorithm for an Under-actuated In-pipe Robot in
  Water Distribution Systems
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
4
The categories of this paper are: cond-mat
2
The categories of this paper are: math
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
0
The categories of this paper are: hep-ph
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an