Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An Integrodifferential Equation for Electromagnetic Fields in Linear
  Dispersive Media   We extend the usual derivation of the wave equation from Maxwell's equations
in vacuum to the case of electromagnetic fields in dispersive homogeneous
isotropic linear media. Usually, dispersive properties of materials are studied
in Fourier space. However, it can be rewarding to consider these properties as
causal functions of time. Due to temporal non locality, this procedure gives
rise to an integrodifferential equation for the electromagnetic fields, which
we also call a wave equation. We have not found this equation in the literature
and we show in this paper why it can be useful.

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The categories of this paper are: eess
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The categories of this paper are: alg-geom
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: supr-con
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The categories of this paper are: gr-qc
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The categories of this paper are: ao-sci
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The categories of this paper are: q-alg
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-th
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The categories of this paper are: q-bio
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The categories of this paper are: atom-ph
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The categories of this paper are: stat