Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: All fundamental electrically charged thin shells in general relativity:
  From star shells to tension shell black holes and regular black holes and
  beyond   We classify all fundamental electrically charged thin shells in general
relativity, i.e., static spherically symmetric perfect fluid thin shells with a
Minkowski spacetime interior and a Reissner-Nordstr\"om spacetime exterior,
characterized by the spacetime mass and electric charge. The fundamental shell
can exist in three states, nonextremal, extremal, and overcharged. The
nonextremal state allows the shell to be located such that its radius can be
outside its own gravitational radius, or can be inside its own Cauchy radius.
The extremal state allows the shell to be located such that its radius can be
outside its own gravitational radius, or can be inside it. The overcharged
state allows the shell to be located anywhere. There is a further division, one
has to specify the orientation of the shell, i.e., whether the normal out of
the shell points toward increasing or decreasing radii. There is still a
subdivision in the extremal state when the shell is at the gravitational
radius, in that the shell can approach it from above or from below. The shell
is assumed to be composed of an electrically charged perfect fluid, and the
energy conditions are tested. Carter-Penrose diagrams are drawn for the shell
spacetimes. There are fourteen cases in the classification of the fundamental
shells, namely, nonextremal star shells, nonextremal tension shell black holes,
nonextremal tension shell regular and nonregular black holes, nonextremal
compact shell naked singularities, Majumdar-Papapetrou star shells, extremal
tension shell singularities, extremal tension shell regular and nonregular
black holes, Majumdar-Papapetrou compact shell naked singularities,
Majumdar-Papapetrou shell quasiblack holes, extremal null shell quasinonblack
holes, extremal null shell singularities, Majumdar-Papapetrou null shell
singularities, overcharged star shells, and overcharged compact shell naked
singularities.

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The categories of this paper are: atom-ph
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The categories of this paper are: supr-con
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-bio
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The categories of this paper are: ao-sci
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The categories of this paper are: acc-phys
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The categories of this paper are: funct-an
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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: q-fin
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The categories of this paper are: physics
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The categories of this paper are: adap-org
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The categories of this paper are: hep-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: econ