Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Structure of Multiloop Amplitudes in Gauge and Gravity Theories   We review the recently discovered duality between color and kinematics in
gauge theories. This duality leads to a remarkably simple double-copy relation
between diagrammatic numerators of gravity scattering amplitudes and
gauge-theory ones. We summarize nontrivial evidence that the duality and
double-copy property holds to all loop orders. We also comment on other
developments, including a proof that the gauge-theory duality leads to the
gravity double-copy property, and the identification of gauge-theory
Lagrangians whose double copies yield gravity Lagrangians.

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The categories of this paper are: dg-ga
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The categories of this paper are: ao-sci
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The categories of this paper are: q-alg
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The categories of this paper are: cmp-lg
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-ex
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The categories of this paper are: supr-con
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The categories of this paper are: quant-ph
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The categories of this paper are: stat
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The categories of this paper are: patt-sol
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The categories of this paper are: alg-geom
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The categories of this paper are: eess
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The categories of this paper are: adap-org
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The categories of this paper are: hep-lat
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The categories of this paper are: chem-ph
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The categories of this paper are: atom-ph