Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum field theory in curved spacetime   An encyclopedia article on mathematical aspects of quantum field theory in
curved spacetime. Section titles are: Introduction and preliminaries;
Construction of *-algebra for a real linear scalar field on globally hyperbolic
spacetimes and some general theorems; Particle creation and the limitations of
the particle concept; Theory of the stress-energy tensor; Hawking and Unruh
effects; Non-globally hyperbolic spacetimes and the time-machine question;
Other related topics and some warnings.

15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom