Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Geodesics in the Engel group with a sub-Lorentzian metric
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
30
The categories of this paper are: q-alg
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
19
The categories of this paper are: eess