Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On Physical Interpretation of the Poynting-Robertson Effect   Comments to the statements of Srikanth (1999) are presented. As for the
standard definition of the Poynting-Robertson drag, the results of Srikanth
(1999) are incorrect. Srikanth's statements about the isothermality condition
and ``red-shift'' are also discussed. Srikanth's results are generalized for
the most general case of the equation of motion when momentum loss per unit
time is proportional to -v/c (higher orders are neglected), where v is
(heliocentric) velocity of the particle, c is the speed of light.

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The categories of this paper are: patt-sol
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The categories of this paper are: mtrl-th
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The categories of this paper are: solv-int
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The categories of this paper are: math-ph
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The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
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The categories of this paper are: acc-phys
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The categories of this paper are: alg-geom
2
The categories of this paper are: math
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The categories of this paper are: econ
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The categories of this paper are: nucl-ex
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-lat
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The categories of this paper are: atom-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