Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Scattering Amplitudes and the CPT theorem in String Theory   We discuss the role of the CPT transformation in first quantized string
theories, both on the world-sheet and in the space-time. We explicitly show
that the space-time CPT theorem holds for all first-quantized (perturbative)
string theories in a Minkowski background of even dimension $D>2$.

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The categories of this paper are: econ
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The categories of this paper are: plasm-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: funct-an
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The categories of this paper are: q-fin
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The categories of this paper are: hep-lat
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The categories of this paper are: q-alg
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The categories of this paper are: ao-sci
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The categories of this paper are: supr-con
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The categories of this paper are: astro-ph
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The categories of this paper are: cs
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The categories of this paper are: cmp-lg
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The categories of this paper are: acc-phys
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The categories of this paper are: math-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: bayes-an