Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cohomogeneity one actions on the three-dimensional Einstein universe   The aim of this paper is to classify the cohomogeneity one conformal actions
on the 3-dimensional Einstein universe $Ein^{1;2}$ , up to orbit equivalence.
In a recent paper [21], we studied the unique (up to conjugacy) irreducible
action of $PSL(2; \mathbb{R})$ on $Ein^{1;2}$ and we showed that the action is
of cohomogeneity one. In the present paper, we determine all the subgroups of
$Conf(Ein^{1;2})$, up to conjugacy, acting reducibly and with cohomogeneity one
on $Ein^{1;2}$. We show that any cohomogeneity one reducible action on
$Ein^{1;2}$ induces a fixed point in the 4-dimensional projective space
$\mathbb{R} \mathbb{P}^4$. Also, we describe all the codimension one induced
orbits by these actions

19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci