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arXiv · 1109.4986

Finite Hilbert stability of (bi)canonical curves

Jarod Alper·Maksym Fedorchuk·David Ishii Smyth
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Abstract

We prove that a generic canonically or bicanonically embedded smooth curve has semistable m-th Hilbert points for all m. We also prove that a generic bicanonically embedded smooth curve has stable m-th Hilbert points for all m \geq 3. In the canonical case, this is accomplished by proving finite Hilbert semistability of special singular curves with G_m-action, namely the canonically embedded balanced ribbon and the canonically embedded balanced double A_{2k+1}-curve. In the bicanonical case, we prove finite Hilbert stability of special hyperelliptic curves, namely Wiman curves. Finally, we give examples of canonically embedded smooth curves whose m-th Hilbert points are non-semistable for low values of m, but become semistable past a definite threshold. (This paper subsumes the previous submission and arXiv:1110.5960).

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Jarod Alper, Maksym Fedorchuk, David Ishii Smyth. 2012-05-04. Finite Hilbert stability of (bi)canonical curves. https://doi.org/10.1007/s00222-012-0403-6

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