Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Heterotic Sigma Models with N=2 Space-Time Supersymmetry   We study the non-linear sigma model realization of a heterotic vacuum with
N=2 space-time supersymmetry. We examine the requirements of (0,2) + (0,4)
world-sheet supersymmetry and show that a geometric vacuum must be described by
a principal two-torus bundle over a K3 manifold.

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The categories of this paper are: hep-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: adap-org
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The categories of this paper are: cmp-lg
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The categories of this paper are: funct-an
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The categories of this paper are: physics
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The categories of this paper are: patt-sol
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The categories of this paper are: nucl-ex
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The categories of this paper are: econ
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The categories of this paper are: chao-dyn
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The categories of this paper are: math-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: cs
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The categories of this paper are: atom-ph
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The categories of this paper are: nlin