Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Multi-loop techniques for massless Feynman diagram calculations   We review several multi-loop techniques for analytical massless Feynman
diagram calculations in relativistic quantum field theories: integration by
parts, the method of uniqueness, functional equations and the Gegenbauer
polynomial technique. A brief, historically oriented, overview of some of the
results obtained over the decades for the massless 2-loop propagator-type
diagram is given. Concrete examples of up to $5$-loop diagram calculations are
also provided.

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The categories of this paper are: chao-dyn
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The categories of this paper are: adap-org
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The categories of this paper are: supr-con
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The categories of this paper are: atom-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: gr-qc
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The categories of this paper are: eess
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The categories of this paper are: physics
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The categories of this paper are: stat
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The categories of this paper are: nlin
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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: chem-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: nucl-th