Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: No hair theorem for bound-state massless static scalar fields outside
  horizonless Neumann compact stars   We study no-hair theorem for horizonless objects, being subject to Neumann
boundary conditions. For massive scalar fields, a no hair theorem for Neumann
compact stars was proved by us in a previous paper, where the nonzero scalar
field mass condition is essential in the proof. In the present work, for
massless scalar fields, we prove a no hair theorem, which claims that
bound-state massless static scalar fields cannot exist outside asymptotically
flat horizonless neutral Neumann compact stars.

29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
6
The categories of this paper are: astro-ph
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga