Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Testing the black hole "no-hair" hypothesis   Black holes in General Relativity are very simple objects. This property,
that goes under the name of "no-hair," has been refined in the last few decades
and admits several versions. The simplicity of black holes makes them ideal
testbeds of fundamental physics and of General Relativity itself. Here we
discuss the no-hair property of black holes, how it can be measured in the
electromagnetic or gravitational window, and what it can possibly tell us about
our universe.

15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol