Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: A Momentum-Conserving Implicit Material Point Method for Surface
  Energies with Spatial Gradients
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
4
The categories of this paper are: cond-mat
14
The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess