Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A degenerate elliptic-parabolic system arising in competitive
  contaminant transport   In this work we investigate a coupled system of degenerate and nonlinear
partial differential equations governing the transport of reactive solutes in
groundwater. We show that the system admits a unique weak solution provided the
nonlinear adsorption isotherm associated with the reaction process satisfies
certain physically reasonable structural conditions. We conclude, moreover,
that the solute concentrations stay non-negative if the source term is
componentwise non-negative and investigate numerically the finite speed of
propagation of compactly supported initial concentrations, in a two-component
test case.

10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th
0
The categories of this paper are: hep-ph
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph