Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The first massive black holes   I briefly outline recent theoretical developments on the formation of the
first massive black holes (MBHs) that may grow into the population of MBHs
powering quasars and inhabiting galactic centers today. I also touch upon
possible observational tests that may give insights on what the properties of
the first MBHs were.

9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
2
The categories of this paper are: math
25
The categories of this paper are: patt-sol