Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Stationary and moving breathers in (2+1)-dimensional O(3) nonlinear
  $\sigma$-model   The formation and evolution of stationary and moving breather solutions in
(2+1)-dimensional O(3) nonlinear $\sigma$-model are investigated. The
analytical form of oscillating solutions for (2+1)-dimensional sine-Gordon
equation, which evolve to periodic (breather) radially symmetric solutions is
determined. On the basis of the found solutions by adding the rotations to the
A3-field vector in isotopic space of S^2, the solutions for the O(3) nonlinear
$\sigma$-model are obtained. By numerical study of the solutions dynamics their
stability in a stationary and a moving state for quite a long time (45000
cycles), although in the presence of weak radiation is shown.

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The categories of this paper are: eess
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
24
The categories of this paper are: dg-ga
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
7
The categories of this paper are: hep-th
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio