Relative Canonical Sheaves of a Family of Curves
نویسنده
چکیده
In this paper we show that the relative canonical sheaf of a relatively minimal fibration of curves over a curve is semi-ample ; in fact, its m-tensored product is base point free for any m ≥ 2. We use Koszul cohomology with it to prove that the relative canonical ring of the fibration is generated in degree up to five.
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