Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An Isomorphism between Scalar-Valued Modular Forms and Modular Forms for
  Weil Representations   In this note, we consider discriminant forms that are given by the norm form
of real quadratic fields and their induced Weil representations. We prove that
there exists an isomorphism between the space of vector-valued modular forms
for the Weil representations that are invariant under the action of the
automorphism group and the space of scalar-valued modular forms that satisfy
some epsilon-condition, with which we translate Borcherds's theorem of
obstructions to scalar-valued modular forms. In the end, we consider an example
in the case of level 12.

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The categories of this paper are: supr-con
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The categories of this paper are: bayes-an
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-ex
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The categories of this paper are: nucl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-ex
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The categories of this paper are: physics
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The categories of this paper are: adap-org
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The categories of this paper are: q-bio
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The categories of this paper are: nlin
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The categories of this paper are: q-alg
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The categories of this paper are: hep-lat
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The categories of this paper are: q-fin
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The categories of this paper are: chem-ph
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The categories of this paper are: eess