Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Blockchain for Trustful Collaborations between Immigrants and
  Governments
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
10
The categories of this paper are: q-bio
2
The categories of this paper are: math