Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Learning Hierarchical Structures with Differentiable Nondeterministic
  Stacks
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
4
The categories of this paper are: cond-mat
6
The categories of this paper are: astro-ph
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
12
The categories of this paper are: nucl-th