Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ptolemy diagrams and torsion pairs in the cluster category of Dynkin
  type A_n   We give a complete classification of torsion pairs in the cluster category of
Dynkin type A_n. Along the way we give a new combinatorial description of
Ptolemy diagrams, an infinite version of which was introduced by Ng. This
allows us to count the number of torsion pairs in the cluster category of type
A_n. We also count torsion pairs up to Auslander-Reiten translation.

30
The categories of this paper are: q-alg
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The categories of this paper are: dg-ga
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
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The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
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The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
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The categories of this paper are: cmp-lg
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The categories of this paper are: funct-an
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex