Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: What are extremal Kerr Killing vectors up to?   In the extremal Kerr spacetime the horizon Killing vector field is null on a
timelike hypersurface crossing the horizon at a fixed latitude, and spacelike
on both sides of the horizon in the equatorial plane. We explain in some detail
how this behaviour is consistent with the existence of timelike Killing vectors
everywhere off the horizon, and how it arises in a limit from the Kerr
spacetime where there is a similar hypersurface strictly outside the horizon.

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The categories of this paper are: nucl-th
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The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
29
The categories of this paper are: funct-an
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The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
6
The categories of this paper are: astro-ph
23
The categories of this paper are: solv-int
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The categories of this paper are: q-alg
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The categories of this paper are: supr-con
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The categories of this paper are: hep-ex
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The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-th
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The categories of this paper are: mtrl-th