Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Aspects of BRST Quantization   BRST-methods provide elegant and powerful tools for the construction and
analysis of constrained systems, including models of particles, strings and
fields. These lectures provide an elementary introduction to the ideas,
illustrated with some important physical applications.

5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ