Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Generalized pp waves in Poincar\'e gauge theory   Starting from the generalized pp waves that are exact vacuum solutions of
general relativity with a cosmological constant, we construct a new family of
exact vacuum solutions of Poincar\'e gauge theory, the generalized pp waves
with torsion. The ansatz for torsion is chosen in accordance with the wave
nature of the solutions. For a subfamily of these solutions, the metric is
dynamically determined by the torsion.

18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
19
The categories of this paper are: eess
17
The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
37
The categories of this paper are: supr-con
23
The categories of this paper are: solv-int