Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Mass in the Hyperbolic Plane   The notions of mass and center of mass are extended to laminae of the
hyperbolic plane. The resulting formulae contain many surprises.

17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
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The categories of this paper are: econ
22
The categories of this paper are: chao-dyn
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The categories of this paper are: eess
9
The categories of this paper are: nlin
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The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics