Hierarchical structure of the family of curves with maximal genus verifying flag conditions

dc.creatorDi Gennaro, Vincenzo
dc.date2005-04-28
dc.date2007-06-23
dc.date.accessioned2026-07-07T08:11:45Z
dc.date.available2026-07-07T08:11:45Z
dc.descriptionFix integers $r,s_1,...,s_l$ such that $1\leq l\leq r-1$ and $s_l\geq r-l+1$, and let $\Cal C(r;s_1,...,s_l)$ be the set of all integral, projective and nondegenerate curves $C$ of degree $s_1$ in the projective space $\bold P^r$, such that, for all $i=2,...,l$, $C$ does not lie on any integral, projective and nondegenerate variety of dimension $i$ and degree $<s_i$. We say that a curve $C$ satisfies the {\it{flag condition}} $(r;s_1,...,s_l)$ if $C$ belongs to $\Cal C(r;s_1,...,s_l)$. Define $ G(r;s_1,...,s_l)=max\left\{p_a(C): C\in \Cal C(r;s_1,...,s_l)\right \}, $ where $p_a(C)$ denotes the arithmetic genus of $C$. In the present paper, under the hypothesis $s_1>>...>>s_l$, we prove that a curve $C$ satisfying the flag condition $(r;s_1,...,s_l)$ and of maximal arithmetic genus $p_a(C)=G(r;s_1,...,s_l)$ must lie on a unique flag such as $C=V_{s_1}^{1}\subset V_{s_2}^{2}\subset ... \subset V_{s_l}^{l}\subset {\bold P^r}$, where, for any $i=1,...,l$, $V_{s_i}^i$ denotes an integral projective subvariety of ${\bold P^r}$ of degree $s_i$ and dimension $i$, such that its general linear curve section satisfies the flag condition $(r-i+1;s_i,...,s_l)$ and has maximal arithmetic genus $G(r-i+1;s_i,...,s_l)$. This proves the existence of a sort of a hierarchical structure of the family of curves with maximal genus verifying flag conditions.
dc.description10 pages, revised version, to appear in Proc. Amer. Math. Soc
dc.identifierhttps://arxiv.org/abs/math/0504576
dc.identifierhttp://arxiv.org/abs/math/0504576
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/132224
dc.subjectAlgebraic Geometry
dc.subject14N15;14H99;14N30;14M05
dc.titleHierarchical structure of the family of curves with maximal genus verifying flag conditions
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