Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Water waves over a time-dependent bottom: Exact description for 2D
  potential flows   Two-dimensional potential flows of an ideal fluid with a free surface are
considered in situations when shape of the bottom depends on time due to
external reasons. Exact nonlinear equations describing surface waves in terms
of the so called conformal variables are derived for an arbitrary time-evolving
bottom parameterized by an analytical function. An efficient numerical method
for the obtained equations is suggested.

34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
24
The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
1
The categories of this paper are: cs