Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Inverse Problem for Static Electromagnetic Field in a Dipole
  Approximation   The following inverse problem is discussed. A static electromagnetic field
generated by a limited system of charges and currents is supposed to be known
with its first derivatives at a point somewhere far from the system. This
allows to reconstruct the position of the system, its net charge, and the
electric and magnetic moments of the system.

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The categories of this paper are: hep-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: solv-int
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The categories of this paper are: hep-lat
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The categories of this paper are: q-bio
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The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: math
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The categories of this paper are: gr-qc
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The categories of this paper are: nlin
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The categories of this paper are: nucl-th
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The categories of this paper are: adap-org
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The categories of this paper are: q-alg
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The categories of this paper are: q-fin