Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Towards a classification of Lorentzian holonomy groups. Part II:
  Semisimple, non-simple weak-Berger algebras   The holonomy group of an (n+2)-dimensional simply-connected, indecomposable
but non-irreducible Lorentzian manifold (M,h) is contained in the parabolic
group $(\mathbb{R} \times SO(n))\ltimes \mathbb{R}^n$. The main ingredient of
such a holonomy group is the SO(n)--projection $G:=pr_{SO(n)}(Hol_p(M,h))$ and
one may ask whether it has to be a Riemannian holonomy group. In this paper we
show that this is always the case, completing our results of the first part
math.DG/0305139. We draw consequences for the existence of parallel spinors on
Lorentzian manifolds.

23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
6
The categories of this paper are: astro-ph
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
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The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg