Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Projective Contact Manifolds   We prove that a projective contact manifold X with second Betti number at
least 2 whose canonical bundle K_X is not nef, is always the projectivised
tangent bundle P(T_Y) of a projective manifold Y. It is expected that the
canonical bundle of a projective contact manifold is never nef; we prove this
unless possibly K_X^2 = 0 and K_X is not numerically trivial. Moreover we study
more generally nef subsheaves of rank 1 in the cotangent bundle which are
proportional to the canonical bundle.

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The categories of this paper are: nucl-th
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: plasm-ph
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The categories of this paper are: stat
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The categories of this paper are: funct-an
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The categories of this paper are: hep-ex
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The categories of this paper are: eess
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The categories of this paper are: nlin
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The categories of this paper are: solv-int
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The categories of this paper are: astro-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: ao-sci
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The categories of this paper are: gr-qc
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The categories of this paper are: adap-org
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The categories of this paper are: q-bio