Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Analytic perturbation theory versus 1/N expansion in the Gross-Neveu
  model   The 1/N expansion can be successfully used to calculate the Green functions
of the two-dimensional O(2N) Gross - Neveu model. In parallel, the methods of
analytic perturbation theory are also applied. Comparing the results of these
two calculations at leading order, we report on the surprising agreement
between them.

21
The categories of this paper are: adap-org
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg