Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An interesting elliptic surface over an elliptic curve   We study the elliptic modular surface attached to the commutator subgroup of
the modular group. This has an elliptic curve as base and only one singular
fibre. We employ an algebraic approach and then consider some arithmetic
questions.

34
The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
8
The categories of this paper are: hep-ex
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
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The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat
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The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
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The categories of this paper are: bayes-an