Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonexistence of Petrov type III Space-Times on which Weyl's Neutrino
  Equation or Maxwell's Equations satisfy Huygens' Principle   Extending previous results we show that there are no Petrov type III
space-times on which either the Weyl neutrino equation or Maxwell's equations
satisfy Huygens' principle. We prove the result by using Maple's NPspinor
package to convert the five-index necessary condition obtained by Alvarez and
Wunsch to dyad form. The integrability conditions of the problem lead to a
system of polynomial equations. We then apply Maple's grobner package to show
that this system has no admissible solutions.

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The categories of this paper are: hep-th
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The categories of this paper are: atom-ph
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The categories of this paper are: q-bio
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The categories of this paper are: adap-org
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The categories of this paper are: eess
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The categories of this paper are: comp-gas
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The categories of this paper are: physics
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The categories of this paper are: chao-dyn
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The categories of this paper are: ao-sci
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The categories of this paper are: nucl-ex
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The categories of this paper are: bayes-an
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The categories of this paper are: cmp-lg
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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: supr-con
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The categories of this paper are: gr-qc