Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Fractionalization and confinement in the U(1) and $Z_2$ gauge theories
  of strongly correlated systems
9
The categories of this paper are: nlin
19
The categories of this paper are: eess
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat