Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Analytical proof of the isospectrality of quasinormal modes for
  Schwarzschild-de Sitter and Schwarzschild-Anti de Sitter spacetimes   The deep reason why the equations describing axial and polar perturbations of
Schwarzschild black holes have the same spectrum is far from trivial. In this
article, we revisit the original proof and try to make it clearer. Still
focusing on uncharged and non-rotating black holes, we extend the results to
spacetimes including a cosmological constant, which have so far mostly been
investigated numerically from this perspective.

13
The categories of this paper are: quant-ph
30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
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The categories of this paper are: eess
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The categories of this paper are: dg-ga
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph