Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: S-duality and Tensionless 5-branes in Compactified Heterotic String
  Theory   We give a simple proof of the known S-duality of Heterotic String theory
compactified on a T^6. Using this S-duality we calculate the tensions for a
class of BPS 5-branes in Heterotic String theory on a circle. One of these, the
Kaluza-Klein monopole, becomes tensionless when the radius of the circle is
equal to the string length. We study the question of stability of the Heterotic
NS5-brane with a transverse circle. For large radii the NS5-brane is absolutely
stable. However for small radii it is only marginally stable. We also study the
moduli space of 2 Kaluza-Klein monopoles and show that it is equal to the
moduli space of a Heterotic A_1 singularity.

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The categories of this paper are: eess
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The categories of this paper are: acc-phys
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The categories of this paper are: q-bio
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The categories of this paper are: supr-con
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The categories of this paper are: q-fin
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The categories of this paper are: funct-an
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The categories of this paper are: hep-lat
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The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
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The categories of this paper are: adap-org
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The categories of this paper are: math-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: plasm-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: mtrl-th
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The categories of this paper are: nlin