Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The leading edge of a free boundary interacting with a line of fast
  diusion   The goal of this work is to explain an unexpected feature of the expanding
level sets of the solutions of a system where a half plane, in which
reaction-diusion phenomena take place, exchanges mass with a line having a
large diusion of its own. The system was proposed by H. Berestycki, L. Rossi
and the second author [4] as a model of enhancement of biological invasions by
a line of fast diusion. It was observed numerically by A.-C. Coulon [7] that
the leading edge of the front, rather than being located on the line, was in
the lower half plane. We explain this behaviour for a free boundary problem
much related to the system for which the simulations were made. We construct
travelling waves for this problem, analyse their free boundary near the line,
and prove that it has the behaviour predicted by the numerical simulations.

35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics