Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Particle models from orientifolds at Gepner-orbifold points   We consider configurations of stacks of orientifold planes and D-branes
wrapped on a non trivial internal space of the structure {(Gepner model)^{c=3n}
x T^{2(3-n)}}/Z_N, for n=1,2,3. By performing simple moddings by discrete
symmetries of Gepner models at orienti fold points, consistent with a Z_N
orbifold action, we show that projection on D-brane configurations can be
achieved, generically leading to chiral gauge theories. Either supersymmetric
or non-supersymmetric (tachyon free) models can be obtained. We illustrate the
procedure through some explicit examples.

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The categories of this paper are: stat
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The categories of this paper are: math
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The categories of this paper are: acc-phys
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The categories of this paper are: cond-mat
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The categories of this paper are: ao-sci
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The categories of this paper are: dg-ga
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The categories of this paper are: math-ph
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The categories of this paper are: q-alg
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The categories of this paper are: supr-con
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The categories of this paper are: cmp-lg
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The categories of this paper are: solv-int
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The categories of this paper are: quant-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: alg-geom
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The categories of this paper are: nucl-th