Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Poincare polynomial for the moduli space $\overline{{\mathcal
  M}_{0,n}}({\mathbb C})$ and the number of points in $\overline{{\mathcal
  M}_{0,n}}({\mathbb F}_q)$   We obtain a combinatorial proof that the number of points of the space
$\overline{{\mathcal M}_{0,n}}({\mathbb F}_q)$ satisfies the recurrent formula
for Poincare polynomials of the space $\overline{{\mathcal M}_{0,n}}({\mathbb
C})$.

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The categories of this paper are: chem-ph
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The categories of this paper are: physics
8
The categories of this paper are: hep-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: cmp-lg
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The categories of this paper are: comp-gas
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The categories of this paper are: bayes-an
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The categories of this paper are: adap-org
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The categories of this paper are: cond-mat
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The categories of this paper are: dg-ga
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The categories of this paper are: acc-phys
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The categories of this paper are: patt-sol
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The categories of this paper are: supr-con
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The categories of this paper are: q-fin
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The categories of this paper are: alg-geom
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The categories of this paper are: gr-qc