Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Critical behaviour of ($2+1$)-dimensional QED: 1/N_f-corrections in the
  Landau gauge   The dynamical generation of a fermion mass is studied within
($2+1$)-dimensional QED with $N$ four-component fermions in the leading and
next-to-leading orders of the 1/N expansion. The analysis is carried out in the
Landau gauge which is supposed to insure the gauge independence of the critical
fermion flavour number, N_c. It is found that the dynamical fermion mass
appears for N<N_c where N_c=3.29, that is only about $1\%$ larger than its
value at leading order.

6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ
27
The categories of this paper are: comp-gas
24
The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
26
The categories of this paper are: bayes-an
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
1
The categories of this paper are: cs