Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On trees covering chains or stars   In this paper, in the context of the ``Dessins d'enfants'' theory, we give a
combinatorial criterion for a plane tree to cover a tree from the classes of
"chains" or "stars''. Besides, we discuss some applications of this result
which are related to the arithmetical theory of torsion on curves.

17
The categories of this paper are: q-fin
18
The categories of this paper are: econ
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
6
The categories of this paper are: astro-ph
13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org