Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: QCD Tests at HERA   Measurements of inclusive jet, dijet and three-jet cross sections in
photon-proton interactions are presented. These measurements provide new tests
of QCD, constrain the parton densities of the photon, and allow searches for
new physics. Measurements of the mean subjet multiplicity are reported and used
to test the differences between quark and gluon jets.

16
The categories of this paper are: stat
2
The categories of this paper are: math
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
24
The categories of this paper are: dg-ga
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg