Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Heavy Flavour Production at HERA   Recent results from the experiments ZEUS and H1 on charm production in $ep$
collisions are reviewed. The topics are elastic and inelastic $J/\psi$
photoproduction, $D^*$ photoproduction differential cross sections and a first
look at the proton structure function F_2^{c\bar{c}}.

10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph