Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Involutions on numerical Campedelli surfaces   Numerical Campedelli surfaces are minimal surfaces of general type with p_g=0
(and so q=0) and K^2=2. Although they have been studied by several authors,
their complete classification is not known. In this paper we classify numerical
Campedelli surfaces with an involution, i.e. an automorphism of order 2. First
we show that an involution on a numerical Campedelli surface S has either four
or six isolated fixed points, and the bicanonical map of S is composed with the
involution if and only if the involution has six isolated fixed points. Then we
study in detail each of the possible cases, describing also several examples.

27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
3
The categories of this paper are: physics
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
8
The categories of this paper are: hep-ex
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
6
The categories of this paper are: astro-ph
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th