Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On some local properties of Yang-Mills vacuum   In this paper we use a non-covariant gauge which makes some of the YM
features manifest which otherwise do not appear explicitly in the Landau gauge
used by Nielsen and Olesen.We show, in fact, that the unstable mode which makes
a large contribution to the vacuum energy is non-perturbative even classically.

32
The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg