Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Canonicity of Baecklund transformation: r-matrix approach. I   For the Hamiltonian integrable systems governed by SL(2)-invariant r-matrix
(such as Heisenberg magnet, Toda lattice, nonlinear Schroedinger equation) a
general procedure for constructing Baecklund transformation is proposed. The
corresponding BT is shown to preserve the Poisson bracket. The proof is given
by a direct calculation using the r-matrix expression for the Poisson bracket.

0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
3
The categories of this paper are: physics
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio