Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Palindromic widths of graph of groups   We prove that the palindromic width of HNN extension of a group by proper
associated subgroups is infinite. We also prove that the palindromic width of
the amalgamated free product of two groups via a proper subgroup is infinite
(except when the amalgamated subgroup has index two in each of the factors).
Combining these results it follows that the palindromic width of the
fundamental group of a graph of groups is mostly infinite.

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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: q-fin
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-ex
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The categories of this paper are: bayes-an
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The categories of this paper are: cond-mat
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The categories of this paper are: acc-phys
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The categories of this paper are: mtrl-th
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The categories of this paper are: eess
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The categories of this paper are: econ
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The categories of this paper are: dg-ga
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The categories of this paper are: physics
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The categories of this paper are: funct-an
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The categories of this paper are: hep-th
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The categories of this paper are: chem-ph