Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On Mean-Field Theory of Quantum Phase Transition in Granular
  Superconductors   In previous work on quantum phase transition in granular superconductors,
where mean-field theory was used, an assumption was made that the order
parameter as a function of the mean field is a convex up function. Though this
is not always the case in phase transitions, this assumption must be verified,
what is done in this article.

14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
17
The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
3
The categories of this paper are: physics
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol