Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Demography of obscured and unobscured AGN: prospects for a Wide Field
  X-ray Telescope   We discuss some of the main open issues in the evolution of Active Galactic
Nuclei which can be solved by the sensitive, wide area surveys to be performed
by the proposed Wide Field X-ray Telescope mission.

2
The categories of this paper are: math
19
The categories of this paper are: eess
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
26
The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int