Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Tips for Deciphering and Quick Calculation of Radiation Spectra   Radiation spectra from ultra-relativistic electrons in thin [$T\ll
l_f(\omega)$] and thick [$T\gg l_f(\omega)$] targets are discussed. The method
of simplified averaging is described by examples of Landau-Pomeranchuk-Migdal
effect and radiation at doughnut scattering. General infrared and ultraviolet
asymptotic properties of radiation spectra are discussed.

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The categories of this paper are: chem-ph
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The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
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The categories of this paper are: q-alg
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The categories of this paper are: dg-ga
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The categories of this paper are: math-ph
9
The categories of this paper are: nlin
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The categories of this paper are: solv-int
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-th
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The categories of this paper are: adap-org
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The categories of this paper are: hep-ex
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The categories of this paper are: mtrl-th
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The categories of this paper are: gr-qc
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The categories of this paper are: patt-sol
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The categories of this paper are: nucl-ex