Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Comparison of integral structures on spaces of modular forms of weight
  two, and computation of spaces of forms mod 2 of weight one, with appendices
  by Jean-Francois Mestre and Gabor Wiese   Two integral structures on the Q-vector space of modular forms of weight two
on X_0(N) are compared at primes p exactly dividing N. When p=2 and N is
divisible by a prime that is 3 mod 4, this comparison leads to an algorithm for
computing the space of weight one forms mod 2 on X_0(N/2). For p arbitrary and
N>4 prime to p, a way to compute the Hecke algebra of mod p modular forms of
weight one on Gamma_1(N) is presented, using forms of weight p, and, for p=2,
parabolic group cohomology with mod 2 coefficients.
  Appendix A is a letter from Mestre to Serre, of October 1987, where he
reports on computations of weight one forms mod 2 of prime level.
  Appendix B reports on an implementation for p=2 in Magma, using Stein's
modular symbols package, with which Mestre's computations are redone and
slightly extended.

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The categories of this paper are: acc-phys
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The categories of this paper are: alg-geom
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The categories of this paper are: gr-qc
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The categories of this paper are: nucl-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: cs
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The categories of this paper are: bayes-an
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The categories of this paper are: physics
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The categories of this paper are: astro-ph
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The categories of this paper are: supr-con
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The categories of this paper are: hep-ex
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The categories of this paper are: solv-int
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The categories of this paper are: q-alg
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The categories of this paper are: q-fin
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The categories of this paper are: chao-dyn
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The categories of this paper are: math-ph