Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Pattern formation of the three-layer Saffman-Taylor problem in a radial
  Hele-Shaw cell
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
18
The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
4
The categories of this paper are: cond-mat
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph
30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas