Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Finite speed of propagation and waiting time for a thin film Muskat
  problem   Finite speed of propagation is established for non-negative weak solutions to
a thin film approximation of the two-phase Muskat problem. The temporal
expansion rate of the support matches the scale invariance of the system.
Moreover, we determine sufficient conditions on the initial data for the
occurrence of waiting time phenomena.

28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
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The categories of this paper are: cmp-lg
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess