Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A (2+1) non-commutative Drinfel'd double spacetime with cosmological
  constant   We show that the Drinfel'd double associated to the standard quantum
deformation $sl_\eta(2,R)$ is isomorphic to the (2+1)-dimensional AdS algebra
with the initial deformation parameter $\eta$ related to the cosmological
constant $\Lambda=-\eta^2$. This gives rise to a generalisation of a
non-commutative Minkowski spacetime that arises as a consequence of the quantum
double symmetry of (2+1) gravity to non-vanishing cosmological constant. The
properties of the AdS quantum double that generalises this symmetry to the case
$\Lambda\neq 0$ are sketched, and it is shown that the new non-commutative AdS
spacetime is a nonlinear $\Lambda$-deformation of the Minkowskian one.

13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol