Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the geometry of the space of oriented lines of the hyperbolic space   Let H be the n-dimensional hyperbolic space of constant sectional curvature
-1 and let G be the identity component of the isometry group of H. We find all
the G-invariant pseudo-Riemannian metrics on the space OG_n of oriented
geodesics of H (modulo orientation preserving reparametrizations). We
characterize the null, time- and space-like curves, providing a relationship
between the geometries of OG_n and H. Moreover, we show that OG_3 is K\"{a}hler
and find an orthogonal almost complex structure on OG_7.

22
The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
3
The categories of this paper are: physics
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
6
The categories of this paper are: astro-ph
35
The categories of this paper are: mtrl-th