Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Composable block solvers for the four-field double porosity/permeability
  model
8
The categories of this paper are: hep-ex
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat