Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Some Remarks on Gravity in Noncommutative Spacetime and a New Solution
  to the Structure Equations
13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th