Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: What's Up with Downward Collapse: Using the Easy-Hard Technique to Link
  Boolean and Polynomial Hierarchy Collapses
11
The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci
3
The categories of this paper are: physics
10
The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math
19
The categories of this paper are: eess
5
The categories of this paper are: gr-qc
4
The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn