On varieties which are uniruled by lines

dc.creatorKnutsen, A. L.
dc.creatorNovelli, C.
dc.creatorSarti, A.
dc.date2005-03-08
dc.date2006-01-12
dc.date.accessioned2026-07-07T06:39:32Z
dc.date.available2026-07-07T06:39:32Z
dc.descriptionUsing the $\sharp$-minimal model program of uniruled varieties we show that for any pair $(X, \H)$ consisting of a reduced and irreducible variety $X$ of dimension $k \geq 3$ and a globally generated big line bundle $\H$ on $X$ with $d:= \H^k$ and $n:= h^0(X, \H)-1$ 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 ${\sharp}$-minimal model of $(X, \H)$ is $(\PP^3,Ø_{\PP^3}(3))$. We also show that the bound is optimal for threefolds.
dc.description19 pages. Corrected version: lemma 2.2 in the previous version removed and substitued by lemma 2.3 in the new version
dc.identifierhttps://arxiv.org/abs/math/0503161
dc.identifierhttp://arxiv.org/abs/math/0503161
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/101113
dc.subjectAlgebraic Geometry
dc.subjectPrimary:14E30,14J30, 14J40, 14N25; Secondary:14C20,14H45
dc.titleOn varieties which are uniruled by lines
dc.typetext

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