Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The early thermalization and HBT puzzles at RHIC   The early thermalization and HBT puzzles in relativistic heavy-ion collisions
studied at RHIC are shortly reviewed. The results of recent hydrodynamic
calculations that shed light on these two intriguing issues are presented. In
particular, the role of the elliptic flow as a signature of early
thermalization is critically examined.

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The categories of this paper are: q-alg
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The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol
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The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
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The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org