Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The calculation of a normal force between multiparticle contacts using
  fractional operators   This paper deals with the complex problem of how to simulate multiparticle
contacts. The collision process is responsible for the transfer and dissipation
of energy in granular media. A novel model of the interaction force between
particles has been proposed and tested. Such model allows us to simulate
multiparticle collisions and granular cohesion dynamics.

33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
4
The categories of this paper are: cond-mat
29
The categories of this paper are: funct-an
20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio