Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A note on the unirationality of a moduli space of double covers   In this note we look at the moduli space $\cR_{3,2}$ of double covers of
genus three curves, branched along 4 distinct points. This space was studied by
Bardelli, Ciliberto and Verra. It admits a dominating morphism $\cR_{3,2} \to
{\mathcal A}_4$ to Siegel space. We show that there is a birational model of
$\cR_{3,2}$ as a group quotient of a product of two Grassmannian varieties.
This gives a proof of the unirationality of $\cR_{3,2}$ and hence a new proof
for the unirationality of ${\mathcal A}_4$.

12
The categories of this paper are: nucl-th
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
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The categories of this paper are: eess
17
The categories of this paper are: q-fin
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The categories of this paper are: econ
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph