Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Invariant spanning trees for quadratic rational maps   We study Thurston equivalence classes of quadratic post-critically finite
branched coverings. For these maps, we introduce and study invariant spanning
trees. We give a computational procedure for searching for invariant spanning
trees. This procedure uses bisets over the fundamental group of a punctured
sphere. We also introduce a new combinatorial invariant of Thurston classes -
the ivy graph.

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The categories of this paper are: econ
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The categories of this paper are: atom-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: chem-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: eess
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ex
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-th
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The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-bio
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The categories of this paper are: patt-sol
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The categories of this paper are: nlin