Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Bell-Szekeres Solution and Related Solutions of the Einstein-Maxwell
  Equations   A novel technique for solving some head-on collisions of plane homogeneous
light-like signals in Einstein-Maxwell theory is described. The technique is a
by-product of a re-examination of the fundamental Bell-Szekeres solution in
this field of study. Extensions of the Bell-Szekeres collision problem to
include light-like shells and gravitational waves are described and a family of
solutions having geometrical and topological properties in common with the
Bell-Szekeres solution is derived.

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The categories of this paper are: alg-geom
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-ex
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The categories of this paper are: solv-int
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The categories of this paper are: atom-ph
21
The categories of this paper are: adap-org
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The categories of this paper are: ao-sci
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The categories of this paper are: comp-gas
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The categories of this paper are: econ
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-ex
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The categories of this paper are: nucl-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: eess
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The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph