Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An Introduction to the Worldline Technique for Quantum Field Theory
  Calculations   These two lectures give a pedagogical introduction to the ``string-inspired''
worldline technique for perturbative calculations in quantum field theory. This
includes an overview over the present range of its applications. Several
examples are calculated in detail, up to the three-loop level. The emphasis is
on photon scattering in quantum electrodynamics.

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The categories of this paper are: adap-org
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The categories of this paper are: eess
4
The categories of this paper are: cond-mat
22
The categories of this paper are: chao-dyn
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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: solv-int
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The categories of this paper are: mtrl-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ex
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The categories of this paper are: astro-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-alg
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The categories of this paper are: nlin
1
The categories of this paper are: cs
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The categories of this paper are: math-ph