Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Avoiding closed timelike curves with a collapsing rotating null dust
  shell   We present an idealised model of gravitational collapse, describing a
collapsing rotating cylindrical shell of null dust in flat space, with the
metric of a spinning cosmic string as the exterior. We find that the shell
bounces before closed timelike curves can be formed. Our results also suggest
slightly different definitions for the mass and angular momentum of the string.

26
The categories of this paper are: bayes-an
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
37
The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys