Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Q4   One of the most fascinating and technically demanding parts of the theory of
two-dimensional integrable systems constitute the models with the spectral
parameter on an elliptic curve, including Landau-Lifshitz and Krichever-Novikov
equations, as well as elliptic Toda and Ruijsenaars-Toda lattices, elliptic
Volterra lattice and Shabat-Yamilov lattice. We explain how all these models
can be unified on the basis of a single equation Q4 on a quad-graph. This
discrete model plays the role of the ``master equation'' in the (sl(2) part of)
2D integrability: most of other models in this area can be obtained from this
one by certain limiting procedures. More precisely, discrete versions of all of
the above mentioned models appear from Q4 imposed on a multi-dimensional cubic
lattice. Zero curvature representations for all models appear as a byproduct of
the general construction.

24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
2
The categories of this paper are: math
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
10
The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex