Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cauchy Problem on Non-globally Hyperbolic Spacetimes   Solutions of the Cauchy problem for the wave equation on a non-globally
hyperbolic spacetime, which contains closed timelike curves (time machines) are
considered. It is proved, that there exists a solution of the Cauchy problem,
it is discontinuous and in some sense unique for arbitrary initial conditions,
which are given on a hypersurface at time, that precedes the formation of
closed timelike curves (CTC). If the hypersurface of initial conditions
intersects the region containing CTC, then the solution of the Cauchy problem
exists only for such initial conditions, that satisfy a certain requirement of
self-consistency.

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The categories of this paper are: cs
6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
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The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
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The categories of this paper are: gr-qc