Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: SDiff(2) KP hierarchy   An analogue of the KP hierarchy, the SDiff(2) KP hierarchy, related to the
group of area-preserving diffeomorphisms on a cylinder is proposed. An improved
Lax formalism of the KP hierarchy is shown to give a prototype of this new
hierarchy. Two important potentials, $S$ and $\tau$, are introduced. The latter
is a counterpart of the tau function of the ordinary KP hierarchy. A
Riemann-Hilbert problem relative to the group of area-diffeomorphisms gives a
twistor theoretical description (nonlinear graviton construction) of general
solutions. A special family of solutions related to topological minimal models
are identified in the framework of the Riemann-Hilbert problem. Further,
infinitesimal symmetries of the hierarchy are constructed. At the level of the
tau function, these symmetries obey anomalous commutation relations, hence
leads to a central extension of the algebra of infinitesimal area-preserving
diffeomorphisms (or of the associated Poisson algebra).

16
The categories of this paper are: stat
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
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The categories of this paper are: nucl-th
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The categories of this paper are: chem-ph
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The categories of this paper are: eess
24
The categories of this paper are: dg-ga
1
The categories of this paper are: cs
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The categories of this paper are: hep-lat
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The categories of this paper are: gr-qc