Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Orbifold cohomology for global quotients   For an orbifold X which is the quotient of a manifold Y by a finite group G
we construct a noncommutative ring with an action of G such that the orbifold
cohomology of X as defined in math.AG/0004129 by Chen and Ruan is the G
invariant part. In the case thar Y is S^n for a surface S with trivial
canonical class we prove that (a small modification of) the orbifold cohomology
of X is naturally isomorphic to the cohomology ring of the Hilbert scheme of n
points on S computed in math.AG/0012166 by Lehn and Sorger.

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The categories of this paper are: mtrl-th
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The categories of this paper are: funct-an
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The categories of this paper are: stat
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The categories of this paper are: hep-th
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The categories of this paper are: dg-ga
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The categories of this paper are: q-fin
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The categories of this paper are: eess
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The categories of this paper are: cond-mat
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The categories of this paper are: chem-ph
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The categories of this paper are: math-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: adap-org
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-th
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The categories of this paper are: econ
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The categories of this paper are: q-alg