Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Second bounded cohomology and WWPD   Given a group acting on a Gromov hyperbolic space, Bestvina and Fujiwara
introduced the WPD property --- weak proper discontinuity --- for studying the
2nd bounded cohomology of the group. We carry out a more general study of
second bounded cohomology using a 'really' weak property discontinuity property
known as WWPD that was introduced by Bestvina, Bromberg, and Fujiwara.

5
The categories of this paper are: gr-qc
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: solv-int
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The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
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The categories of this paper are: stat
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The categories of this paper are: atom-ph
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The categories of this paper are: econ
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The categories of this paper are: acc-phys
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-lat
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The categories of this paper are: supr-con
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The categories of this paper are: nucl-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: nlin