Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Well-posedness and ill-posedness results for the Novikov-Veselov
  equation   In this paper we study the Novikov-Veselov equation and the related modified
Novikov-Veselov equation in certain Sobolev spaces. We prove local
well-posedness in H^s (R2) for s > 1/2 for the Novikov-Veselov equation, and
local well-posedness in H^s (R2) for s > 1 for the modified Novikov-Veselov
equation. Finally we point out some ill-posedness issues for the Novikov-
Veselov equation in the supercritical regime.

6
The categories of this paper are: astro-ph
23
The categories of this paper are: solv-int
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio