Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Understanding Heavy Quarkonium Systems in Perturbative QCD   We review the recent theoretical progress in heavy quarkonium spectroscopy
within the boundstate theory based on perturbative QCD. New microscopic
pictures of the heavy quarkonium systems are obtained.

7
The categories of this paper are: hep-th
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The categories of this paper are: nucl-th
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The categories of this paper are: q-fin
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
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The categories of this paper are: quant-ph
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The categories of this paper are: cond-mat
27
The categories of this paper are: comp-gas
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The categories of this paper are: nucl-ex
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The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph