Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Groebner Bases for Transportation Polytopes   The toric ideals of $3\times 3$ transportation polytopes $T$ are
quadratically generated. The only exception is the Birkhoff polytope $B_3$.
  If $T$ is not a multiple of $B_3$, these ideals even have squarefree
quadratic initial ideals. This class contains all smooth $3 \times 3$
transportation polytopes.

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The categories of this paper are: gr-qc
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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: astro-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: alg-geom
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The categories of this paper are: patt-sol
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The categories of this paper are: chem-ph
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The categories of this paper are: dg-ga
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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: ao-sci
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The categories of this paper are: q-bio
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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: quant-ph