Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Robust a posteriori error estimators for mixed approximation of nearly
  incompressible elasticity
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ