Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the group of automorphisms of Horikawa surfaces   Minimal algebraic surfaces of general type $X$ such that
$K^2_X=2\chi(\mathcal{O}_X)-6$ are called Horikawa surfaces. In this note the
group of automorphisms of Horikawa surfaces is studied. The main result states
that given an admissible pair $(K^2, \chi)$ such that $K^2=2\chi-6$, every
connected component of Gieseker's moduli space $\mathfrak{M}_{K^2,\chi}$
contains an open subset consisting of surfaces with group of automorphisms
isomorphic to $\mathbb{Z}_2$.

18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
15
The categories of this paper are: nucl-ex
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
26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga