On the higher Wahl maps (Q1340396)

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scientific article; zbMATH DE number 701549
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On the higher Wahl maps
scientific article; zbMATH DE number 701549

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    On the higher Wahl maps (English)
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    19 December 1994
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    Let \(C\) be a complete nonsingular curve of genus \(g\) over an algebraically closed field \(k\), and \({\mathcal L}\) an invertible sheaf over \(C\) of positive degree. Generalising a construction of \textit{J. Wahl} [J. Differ. Geom. 32, No. 1, 77-98 (1990; Zbl 0724.14022)] the author defines a map \[ \Phi^{(n)} : \bigwedge^n \Gamma (C, {\mathcal L}) \to \Gamma (C, \omega_C^{ \otimes 1/2n (n - 1)} \otimes {\mathcal L}^{\otimes n}) \] whose surjectivity is related to linear normality of generalised dual curves of \(C\). His main theorem states that if \(\text{char} k > \deg {\mathcal L} > (g - 1) (2n^2 - 2n + 3) + 2(n^2 - 1)\) then \(\Phi^{(n)}\) is surjective. The proof seems to be similar to arguments in Wahl's paper; the presentation of the paper is rather formal.
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    Wahl map
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    dual curves
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