Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The maximal unipotent finite quotient, unusual torsion in Fano
  threefolds, and exceptional Enriques surfaces   We introduce and study the maximal unipotent finite quotient for algebraic
group schemes in positive characteristics. Applied to Picard schemes, this
quotient encodes unusual torsion. We construct integral Fano threefolds where
such unusual torsion actually appears. The existence of such threefolds is
surprising, because the torsion vanishes for del Pezzo surfaces. Our
construction relies on the theory of exceptional Enriques surfaces, as
developed by Ekedahl and Shepherd-Barron.

13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
24
The categories of this paper are: dg-ga
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th