Using the #-minimal model program of uniruled varieties we show that, for any pair (X, H) consisting of a reduced and irreducible variety X of dimension k >= 3 and a globally generated big line bundle R on X with d := H-k and n := h(o)(X,H) - 1 such that d < 2(n - k) - 4, then X is uniruled of H-degree one, except if (k, d, n) = (3, 27,19) and a #-minimal model of (X,H) is (P-3, O-P3(3)). We also show that the bound is optimal for threefolds

Knutsen, A., Novelli, C., Sarti, A. (2006). On varieties that are uniruled by lines. COMPOSITIO MATHEMATICA, 142(4), 889-906 [10.1112/S0010437X06002089].

On varieties that are uniruled by lines

Novelli, C;
2006

Abstract

Using the #-minimal model program of uniruled varieties we show that, for any pair (X, H) consisting of a reduced and irreducible variety X of dimension k >= 3 and a globally generated big line bundle R on X with d := H-k and n := h(o)(X,H) - 1 such that d < 2(n - k) - 4, then X is uniruled of H-degree one, except if (k, d, n) = (3, 27,19) and a #-minimal model of (X,H) is (P-3, O-P3(3)). We also show that the bound is optimal for threefolds
Articolo in rivista - Articolo scientifico
minimal model program; rational curves; 3-folds; n-folds; linear systems
English
2006
142
4
889
906
none
Knutsen, A., Novelli, C., Sarti, A. (2006). On varieties that are uniruled by lines. COMPOSITIO MATHEMATICA, 142(4), 889-906 [10.1112/S0010437X06002089].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/10330
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