Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Analysis of Dynamic Axial-Symmetric Shells   The aim of this work is to analyze the dynamical behavior of relativistic
infinite axial-symmetric shells with flat interior and a radiation filled
curved exterior spacetimes. It will be proven, by the use of conservation
equations of Israel, that the given configuration does not let expansion or
collapse of the shell which was proposed before, but rather the shell stays at
constant radius. The case of null-collapse will also be considered in this work
and it will be shown that the shell collapses to zero radius, and moreover, if
cylindrical flatness is imposed a boundary layer is obtained still contrary to
previous works.

23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
6
The categories of this paper are: astro-ph
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an