Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Boundary scattering in the principal chiral model   An informal introduction to our recent work on the principal chiral model
with boundary. We found that both classically integrable boundary conditions
and quantum boundary S-matrices were classified by the symmetric spaces G/H.
The connection is explained by the presence of a twisted Yangian algebra of
non-local charges.

13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
6
The categories of this paper are: astro-ph
27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph
23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org