Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Elementary equivalence vs commensurability for hyperbolic groups   We study to what extent torsion-free (Gromov)-hyperbolic groups are
elementarily equivalent to their finite index subgroups. In particular, we
prove that a hyperbolic limit group either is a free product of cyclic groups
and surface groups, or admits infinitely many subgroups of finite index which
are pairwise non elementarily equivalent.

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The categories of this paper are: eess
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The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
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The categories of this paper are: econ
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The categories of this paper are: funct-an
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The categories of this paper are: cmp-lg
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The categories of this paper are: astro-ph
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: supr-con
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The categories of this paper are: bayes-an
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The categories of this paper are: quant-ph
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The categories of this paper are: q-fin
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The categories of this paper are: gr-qc
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The categories of this paper are: stat