Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The emergence of background geometry from quantum fluctuations   We show how the quantization of two-dimensional gravity leads to an
(Euclidean) quantum space-time where the average geometry is that of constant
negative curvature and where the Hartle-Hawking boundary condition arises
naturally.

32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
6
The categories of this paper are: astro-ph
14
The categories of this paper are: math-ph