Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum gravity and spin systems   A new method for nonperturbative investigations of quantum gravity is
presented in which the simplicial path integral is approximated by the
partition function of a spin system. This facilitates analytical and numerical
computations considerably. In two dimensions equivalence to an Ising model with
ternary couplings is recovered. First simulations in four dimensions indicate
strong similarities to the phase structure of original Regge theory.

28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
4
The categories of this paper are: cond-mat
17
The categories of this paper are: q-fin
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex