Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Analytic approximations to the spacetime of a critical gravitational
  collapse   We present analytic expressions that approximate the behavior of the
spacetime of a collapsing spherically symmetric scalar field in the critical
regime first discovered by Choptuik. We find that the critical region of
spacetime can usefully be divided into a ``quiescent'' region and an
``oscillatory'' region, and a moving ``transition edge'' that separates the two
regions. We find that in each region the critical solution can be well
approximated by a flat spacetime scalar field solution. A qualitative nonlinear
matching of the solutions across the edge yields the right order of magnitude
for the oscillations of the discretely self-similar critical solution found by
Choptuik.

21
The categories of this paper are: adap-org
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
15
The categories of this paper are: nucl-ex
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph