Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spacetime Foam and the Cosmological Constant   In the saddle point approximation, the Euclidean path integral for quantum
gravity closely resembles a thermodynamic partition function, with the
cosmological constant $\Lambda$ playing the role of temperature and the
``density of topologies'' acting as an effective density of states. For
$\Lambda<0$, the density of topologies grows superexponentially, and the sum
over topologies diverges. In thermodynamics, such a divergence can signal the
existence of a maximum temperature. The same may be true in quantum gravity:
the effective cosmological constant may be driven to zero by a rapid rise in
the density of topologies.

26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat