Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A gauge-invariant Hamiltonian analysis for non-Abelian gauge theories in
  (2+1) dimensions   The Hamiltonian formulation for a non-Abelian gauge theory in two spatial
dimensions is carried out in terms of a gauge-invariant matrix parametrization
of the fields. The Jacobian for the relevant transformation of variables is
given in terms of the WZW-action for a hermitian matrix field. Some
gauge-invariant eigenstates of the kinetic term of the Hamiltonian are given;
these have zero charge and exhibit a mass gap.

24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph