Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum mechanics and gravity as preclusion principles of four
  dimensional geometries   The goal of this paper is to employ a "preclusion principle" originally
suggested by Rafael Sorkin in order to come up with a relativistically
covariant model of quantum mechanics and gravity. Space-time is viewed as
geometry as opposed to dynamics, and "unwanted" histories in that geometry are
precluded.

10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg
13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga