Bounds for sectional genera of varieties invariant under Pfaff fields (Q384306)
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scientific article; zbMATH DE number 6233917
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | Bounds for sectional genera of varieties invariant under Pfaff fields |
scientific article; zbMATH DE number 6233917 |
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Bounds for sectional genera of varieties invariant under Pfaff fields (English)
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27 November 2013
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Poincaré problem
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sectional genus
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Pfaff field
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invariant varitey
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0.70961684
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0.67897636
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0.6748438
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0.6723195
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0.67136097
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0.6692611
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The abstract says: ``We establish an upper bound for the sectional genus of varieties which are invariant under Pfaff fields on projective spaces''. A more detailed summary should at least (assuming the reader is familiar with the nomenclature) include the statement of their results:NEWLINENEWLINE{Theorem.} Let \(X\) be a nonsingular projective variety of dimension \(m\) which is invariant under a Pfaff field \({\mathcal F}\) of rank \(k\) on \({\mathbb P}^n\); assume that \(m \geq k\). If the tangent bundle \(\Theta_{X}\) is stable, then NEWLINE\[NEWLINE \frac{2g(X, {\mathcal O}_X(1))-2}{\deg(X)} \leq \frac{\deg({\mathcal F})-k}{\binom{m-1}{k-1}}+m-1. NEWLINE\]NEWLINENEWLINENEWLINE{ Theorem.} Let \(X\subset {\mathbb P}^n\) be a Gorenstein projective variety nonsingular in codimension \(1\), which is invariant under a Pfaff field \({\mathcal F}\) on \({\mathbb P}^n\) whose rank is equal to the dimension of \(X\). Then NEWLINE\[NEWLINE \frac{2g(X, {\mathcal O}_X(1))-2}{\deg(X)} \leq \deg({\mathcal F}) - 1. NEWLINE\]NEWLINENEWLINENEWLINEThis result generalizes the bounds in [\textit{A. Campillo} et al., J. Lond. Math. Soc., II. Ser. 62, No. 1, 56--70 (2000; Zbl 1040.32027)].
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