Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Wormholes, naked singularities and universes of ghost radiation   Both the static and homogeneous metrics describing the spherically symmetric
gravitational field of a crossflow of incoming and outgoing null dust streams
are generalized for the case of the two-component ghost radiation. Static
solutions represent either naked singularities or the wormholes recently found
by Hayward. The critical value of the parameter separating the two
possibilities is given. The wormhole is allowed to have positive mass. The
homogeneous solutions are open universes.

2
The categories of this paper are: math
7
The categories of this paper are: hep-th
19
The categories of this paper are: eess
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci