Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Type III contractions and quintic threefolds   We study type III contractions of Calabi-Yau threefolds containing a ruled
surface over a smooth curve. We discuss the conditions necessary for the image
threefold to by smoothable. We describe the change in Hodge numbers caused by
this contraction and smoothing deformation. A generalization of a fomula for
calculating Hodge numbers of hypersurfaces in $\mathbb{P}^4$ with ordinary
double and triple points is presented. We use these results to construct new
Calabi-Yau threefolds of Picard rank two arising from a family of quintic
threefolds containing a cone.

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The categories of this paper are: chem-ph
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The categories of this paper are: solv-int
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The categories of this paper are: nucl-ex
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The categories of this paper are: physics
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The categories of this paper are: mtrl-th
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The categories of this paper are: gr-qc
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The categories of this paper are: patt-sol
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The categories of this paper are: q-alg
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The categories of this paper are: cond-mat
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The categories of this paper are: supr-con
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-lat
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The categories of this paper are: comp-gas
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The categories of this paper are: adap-org
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The categories of this paper are: plasm-ph
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The categories of this paper are: astro-ph