Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The space density of magnetic and non-magnetic cataclysmic variables,
  and implications for CV evolution   We present constraints on the space densities of both non-magnetic and
magnetic cataclysmic variables, and discuss some implications for models of the
evolution of CVs. The high predicted non-magnetic CV space density is only
consistent with observations if the majority of these systems are extremely
faint in X-rays. The data are consistent with the very simple model where
long-period IPs evolve into polars and account for the whole short-period polar
population. The fraction of WDs that are strongly magnetic is not significantly
higher for CV primaries than for isolated WDs. Finally, the space density of
IPs is sufficiently high to explain the bright, hard X-ray Galactic Centre
source population.

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The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th
3
The categories of this paper are: physics
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph